EX A – Five-Way Intersection Project Final EIR — Napa City Council, September 15, 2026 (part 1 of 2)

Five-Way Intersection Improvements
Project

NAPA, CALIFORNIA
DISTRICT 4 –NAP–121 (PM 7.2/7.5)
0J890/0414000097
Final Environmental Impact Report/
Environmental Assessment with Finding of No
Significant Impact and Final Section 4(f)
Evaluation
Prepared by the
State of California, Department of Transportation
and the City of Napa
The environmental review, consultation, and any other actions required by applicable Federal environmental laws for this project are being, or have been, carried out by Caltrans pursuant to 23 USC 327 and the Memorandum of Understanding dated May 27, 2022, and executed by FHWA and Caltrans.

July 2026

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Five-Way Intersection Improvements i Final EIR/EA
Napa, California July 2026
General Information about This Document
The California Department of Transportation (Caltrans), as assigned by the Federal Highway Administration (FHWA), has prepared this Environmental Impact Report/Environmental Assessment with Finding of No Significant Impact for the proposed project located in the City of Napa. Caltrans is the lead agency under the National Environmental Policy Act (NEPA). The City of Napa is the lead agency under the California Environmental Quality Act (CEQA). The document tells you why the project is being proposed, what alternatives have been considered for the project, the preferred alternative for the project, how the existing environment could be affected by the project, the potential impacts of each of the alternatives, and the proposed avoidance, minimization, and/or mitigation measures. The Draft Environmental Impact Report/Environmental Assessment circulated to the public for 65 days between August 28, 2025 and November 1, 2025. Comments received during this period are included in Chapter 4.4 Draft EIR/EA Comments and Responses. Changes made to the document since the draft document circulation are shown with a vertical line in the margin. Minor editorial changes and clarifications are not shown. Additional copies of this document and the related technical studies are available for review at Caltrans District 4, 111 Grand Avenue, Oakland, CA 94612 or the City of Napa Community Services Building at 1600 First Street, Napa, CA 94559 on weekdays from 8:00am to 5:00pm. This document may be downloaded at the following website: https://dot.ca.gov/caltrans-near- me/district-4/d4-popular-links/d4-environmental-docs.

Alternative Formats:

For individuals with sensory disabilities, this document can be made available in Braille, in large print, on audiocassette, or on computer disk. To obtain a copy in one of these alternate formats, please call or write to Caltrans District 4 Office Of Environmental Analysis, P.O. Box 23660, MS-8B, Oakland, CA 94623-0660, Attn: Shawn Hallum; 510- 406-9808 (Voice), or use the California Relay Service 1 (800) 735-2929 (TTY to Voice), 1 (800) 735-2922 (Voice to TTY), 1 (800) 855-3000 (Spanish TTY to Voice and Voice to TTY), 1-800-854-7784 (Spanish and English Speech-to-Speech) or 711.

EXHIBIT A
Five-Way Intersection Improvements ii Final EIR/EA
Napa, California July 2026
SCH# 2024071257 04-NAP-121-PM 7.2 /7.5
0J890/0414000097
Improve the State Route 121 intersection with Third Street, Coombsville Road, and East Avenue, within the City of Napa (Postmile 7.2 to Postmile 7.5).

Final Environmental Impact Report/Environmental Assessment with Finding of No Significant Impact and Final Section 4(f) Evaluation Submitted Pursuant to: (State) Division 13, California Public Resources Code (Federal) 42 USC 4332(2)(C) and 49 USC 303

THE STATE OF CALIFORNIA
Department of Transportation
and
City of Napa
Responsible Agencies: Napa Valley Transportation Authority, California Transportation Commission
_______________
Date
_______________
Date
____________________________
Doanh Nguyen
Acting District Director
California Department of Transportation
NEPA Lead Agency
____________________________
Jessica Lowe
Public Works Director
City of Napa
CEQA Lead Agency
The following persons may be contacted for more information about this document:

Caltrans District 4 – Office of Environmental Analysis City of Napa ATTN: Shawn Hallum ATTN: Guy Preston
P.O Box 23660 1600 First Street
Oakland, CA 94623-0660 Napa, CA 94559
510-406-9808 707-257-9673

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Five-Way Intersection Improvements iii Final EIR/EA
Napa, California July 2026

CALIFORNIA DEPARTMENT OF TRANSPORTATION

FINDING OF NO SIGNIFICANT IMPACT (FONSI)
FOR
Five-Way Intersection Improvements Project
The California Department of Transportation (Caltrans) has determined that the Five- Way Intersection Improvement Project will have no significant impact on the human environment. This FONSI is based on the attached Environmental Assessment (EA), which has been independently evaluated by Caltrans and determined to adequately and accurately discuss the need, environmental issues, and impacts of the proposed project and appropriate mitigation measures. It provides sufficient evidence and analysis for determining that an Environmental Impact Statement is not required. Caltrans takes full responsibility for the accuracy, scope, and content of the attached EA.

The environmental review, consultation, and any other actions required by applicable Federal environmental laws for this project are being, or have been, carried out by Caltrans pursuant to 23 USC 327 and the Memorandum of Understanding dated May 27, 2022, and executed by FHWA and Caltrans.

Doanh Nguyen
Acting District Director
California Department of Transportation
Date

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Five-Way Intersection Improvements iv Final EIR/EA
Napa, California July 2026
Summary
S-1 NEPA ASSIGNMENT
Since 2007, Caltrans has performed federal responsibilities for environmental decisions and approvals under NEPA for highway projects in California that are funded or otherwise approved by FHWA. These responsibilities have been assigned to Caltrans by FHWA pursuant to Title 23 United States Code (USC) Sections 326 and 327 and two Memoranda of Understanding signed by FHWA. Please see the Caltrans Standard Environmental Reference (SER) Volume 1, Chapter 38, “NEPA Assignment” for additional information.

S-2 PROJECT OVERVIEW
S-2.1 Lead Agencies and NEPA/CEQA Documentation
The proposed project is a joint project by Caltrans and FHWA and is subject to state and federal environmental review requirements. Project documentation, therefore, has been prepared in compliance with both CEQA and NEPA. The City of Napa is the lead agency under CEQA and Caltrans is the lead agency under NEPA.

Some impacts determined to be significant under CEQA may not lead to a determination of significance under NEPA. Because NEPA is concerned with the significance of the project as a whole, often a “lower level” document is prepared for NEPA.

Following receipt of public comments on the Draft EIR/EA and preparation of this Final EIR/EA, the City of Napa will consider certification that the Project complies with CEQA and will adopt findings for significant impacts identified and mitigation measures that will be included as a condition of project approval. The Project would result in significant and unavoidable impacts to cultural resources and, therefore, a Statement of Overriding Considerations is required for project approval. A Notice of Determination will be filed with the State Clearinghouse. Caltrans determined that the NEPA action does not significantly affect the environment. Caltrans has issued a Finding of No Significant Impact (FONSI) in accordance with NEPA. A Notice of Availability (NOA) of the FONSI will be sent to the affected units of federal, state, and local government, and to the State Clearinghouse in compliance with Executive Order 12372. A Notice of Statute of Limitations will also be filed in the Federal Register by FHWA.

S-2.2 Project Area
The proposed Five-Way Intersection Improvements Project (Project) is located in the City of Napa on State Route (SR) 121 at the existing intersection with Third Street, Coombsville Road, and East Avenue.

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S-2.3 Purpose and Need
Purpose
The purpose of the Project is to improve the operations of the intersection that will result in reduced driver delay, reduced congestion, and, therefore, an overall improvement to intersection operations. Additionally, the purpose of the Project is to improve the safety and accessibility for all users of the intersection. The secondary objectives of this Project are to improve bicycle and pedestrian facilities at the intersection as well as meet Americans with Disabilities Act (ADA) requirements.

Need
The Project intersection needs geometric improvements to improve the operations, efficiency, and capacity of the intersection. In addition, safety improvements are needed to reduce collisions through the SR 121 corridor, which is ranked among the highest injury corridors within the City of Napa per the City’s Local Roadway Safety Plan (adopted September 6, 2022). Data was obtained and analyzed from both the Caltrans Traffic Accident Surveillance and Analysis System (TASAS) and the City of Napa Police Department for the latest 5-year period in the Project area along SR 121. There were ten reported collisions within the Project area, which resulted in a higher than statewide average rate for similar facilities.

Traffic studies conducted by the City of Napa have shown that the intersection has operated at a Level of Service (LOS) D since at least the year 2000. Although the intersection is already operating at an unacceptable LOS, operations will continue to deteriorate due to the continued growth of the area and continued increase in vehicular demand on this intersection, as documented in the Napa-Solano Travel Demand Model.

The existing intersection has limited and substandard pedestrian facilities, including long, skewed crosswalks and narrow sidewalks, that increase pedestrian exposure to vehicle conflicts throughout the five-legged intersection. Existing pedestrian facilities do not meet current ADA standards. There are discontinuous sidewalks on the northwest and southwest sides of SR 121 that extend for approximately 50 feet and 200 feet, but no other sidewalks exist at the intersection. The existing intersection also does not provide bicycle facilities, resulting in a disconnect in the existing bicycle facilities along Third Street, Coombsville Road, and East Avenue.

S-2.4 Proposed Action
This Final EIR/EA evaluates the “Build Alternative” and the “No Build Alternative”.

Build Alternative
The Build Alternative would make improvements to the SR 121/Third Street/ Coombsville Road/East Avenue Intersection in the City of Napa (Napa County, California). The Build Alternative would replace the existing intersection with two, single- lane roundabouts designed to accommodate the Design Year traffic forecast volumes which have been projected to 2046. The northern roundabout has four legs and includes SR 121, Third Street, and East Avenue. The southern roundabout has three legs and includes SR 121 and Coombsville Road. The Build Alternative meets the

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Five-Way Intersection Improvements vi Final EIR/EA
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purpose and need of the Project by improving operations and safety for all modes of travel while addressing future mobility needs.

No Build Alternative
The No Build Alternative leaves the existing lane geometrics and intersection controls in place, without a roundabout. Under existing conditions, the intersection of SR 121/Third Street/Coombsville Road/East Avenue remains signalized. This alternative does not meet the purpose and need for the Project to improve intersection operations.

S-3 PROJECT IMPACTS
Summary Table 1 provides a brief summary of the environmental impacts of the Build and No Build Alternatives, as well as avoidance, minimization, and/or mitigation measures. The analyses contained in this Final EIR/EA determined that neither the Build Alternative nor the No Build Alternative would result in impacts to the following resources:
• Coastal Zone
• Wild and Scenic Rivers
• Parks and Recreational Facilities
• Farmlands
• Timberlands
• Community Character and Cohesion
• Wetlands and Other Waters
• Plant Species
• Invasive Species
Therefore, these impact categories were not included in Summary Table 1. Detailed discussions of the existing setting, impacts, and avoidance, minimization, and/or mitigation measures are provided in Chapter 2 of this Final EIR/EA.

Summary Table 1: Summary of Major Potential Impacts from Alternatives Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
Existing and Future
Land Use
Would acquire one
full residential
property and
incorporate into the
proposed
roundabout
facilities.

No effect. None required.

Consistency with
State, Regional,
and Local Plans
and Programs
Consistent Inconsistent None required
Growth Would facilitate
planned growth;
would not result in
unplanned growth
Potential limit to
planned growth as
congestion
worsens
None required

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Five-Way Intersection Improvements vii Final EIR/EA
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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
Relocations and
Real Property
Acquisition
Would acquire one
full residential
property and result
in minor impacts to
other residential
and commercial
properties.

No effect MM-RRP-1.1: The Project would
comply with all requirements of the
Uniform Relocation Act to ensure
residents displaced by the Project
would be properly compensated
and relocated, as necessary.

Utilities and
Emergency
Services
Would relocate and
adjust existing
utility lines, would
not result in
increased demand.

Emergency access
would be
maintained
throughout
construction and
benefitted by
improved
operational
conditions.

No effect None required
Traffic and
Transportation/
Pedestrian and
Bicycle Facilities
Beneficial due to
less vehicle delay
and improved
bicycle and
pedestrian facilities.

Congestion and
vehicle delay would
worsen over time
None required
Visual/Aesthetics Would result in
removal of trees
and a contributing
resource to a
historic district and
introduce new
lighting and
retaining walls
No effect AMM VIS-1.1: The Project shall
survey exact locations of existing
trees and include the tree locations
in the plan set during the design
phase. Where the pruning of trees
is required to accommodate
construction operations, pruning
shall be done under the
supervision of a certified arborist.

AMM VIS-1.2: Where feasible, the
roundabout island, medians, and
parkway strips shall be landscaped
with a combination of trees and
ornamental planting. Decorative
paving shall be incorporated for
areas too narrow to plant or where
planting is not easily maintained.

AMM VIS-1.3: Retaining walls,
barriers, paving, and roundabouts
shall incorporate aesthetic
treatments that use context-
sensitive design, textures, and/or
colors to help minimize glare and
support visual unity at the Project
site.

AMM VIS-1.4: During construction
operations, unsightly material and

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Five-Way Intersection Improvements viii Final EIR/EA
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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
equipment in staging areas shall
be placed where they are less
visible and/or covered where
possible. Construction activities
shall limit all construction lighting
to within the area of work and
avoid light trespass in residential
areas through directional lighting,
shielding, and other measures as
needed.

AMM VIS-1.5: Light added as
permanent features shall be
shielded to the extent feasible and
light trespass shall be minimized.

Cultural Resources Requires
demolition and
removal of a
contributing
resource to a
historic district; it is
anticipated that the
removal would
result in an adverse
effect to the
district’s historical
integrity.

No effect MM CULT-1.1: Historic Resource
Preservation: Following
construction, the Project Sponsor
will prepare, in consultation with
the State Historic Preservation
Officer (SHPO), an evaluation of
the East Napa Historic District for
eligibility to the National Register
of Historic Places. In consultation
with Section 106 stakeholders and
the SHPO, Caltrans and the City of
Napa will implement mitigation
measures specific to the effects to
the East Napa Historic District,
including, but not limited to,
installation of identification signs
and interpretive materials providing
information on the history of the
neighborhood, and recordation of
801 Silverado Trail consistent with
the Historic American Building
Survey (HABS) standards
maintained in local repositories.

These mitigation measures are
captured in a Memorandum of
Agreement between Caltrans as
the NEPA lead agency, the
stakeholders, and the SHPO.

Hydrology and
Floodplain
Minor floodplain
encroachment
No effect None required
Water Quality and
Storm Water
Runoff
Short-term
degradation of
water quality may
occur from
construction
activities, Project
would result in 0.30
acres of net new
No effect AMM WQ-1.1: Prior to any soil
disturbance work, file a Notice of
Intent with State Water Resources
Control Board (SWRCB). To
maintain proper permit coverage
under the Construction Stormwater
General Permit (CGP), in addition
to filing a Notice of Intent, all
dischargers must electronically file

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Five-Way Intersection Improvements ix Final EIR/EA
Napa, California July 2026
Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
impervious
surfaces
permit registration documents,
Notice of Termination, changes of
information, sampling and
monitoring information, annual
reporting, and other required
compliance documents through the
SWRCB’s Stormwater Multiple
Application and Report Tracking
System (SMARTS).

AMM WQ-1.2: Prepare and
implement a Stormwater Pollution
Prevention Plan (SWPPP). Prior to
the start of construction, the
SWPPP would be submitted by the
Contractor to Caltrans for
approval. The SWPPP shall detail
the measures to address the
temporary water quality impacts
resulting from construction
activities associated with this
Project. The SWPPP shall also
include the development of a
Construction Site Monitoring
Program that presents procedures
and methods related to the visual
monitoring, sampling, and analysis
plans during construction of the
Project.

Additionally, the treatment BMP
certifications will be prepared and
provided at various milestones of
the Project.

Geology, Soils,
Seismicity and
Topography
The Project site is
not located within
an active fault zone
but would be
subject to strong
ground shaking in
the event of an
earthquake. The
majority of the
Project site has low
potential for
landslides and
there does not
appear to be
potential for
liquefaction.

The Project site is
not located within
an active fault zone
but would be
subject to strong
ground shaking in
the event of an
earthquake. The
majority of the
Project site has low
potential for
landslides and
there does not
appear to be
potential for
liquefaction.

Additional laboratory tests shall
also include moisture content, unit
weight, plasticity indexes and liquid
limits, particle size analyses,
consolidation, strength tests, and
corrosivity testing.

Paleontology The Project is
unlikely to disturb
No effect None required.

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Five-Way Intersection Improvements x Final EIR/EA
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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
paleontological
resources.

Hazardous Waste
and Materials
Construction
workers could be
exposed to lead-
based paint,
aerially deposited
lead, petroleum-
hydrocarbons,
asbestos-
containing
materials, and
treated wood
waste.

No effect AMM HM-1.1: Testing for the
presence of lead-based paint and
asbestos-containing materials, on
the existing structure at 801
Silverado Trail and roadway paint
to be removed shall occur. If these
substances are found to be
present, applicable regulations
pertaining to their removal and
disposal shall be followed.

AMM HM-1.2: Testing of the soils
within the project area for worker
safety and soil management
purposes shall occur. Soils and
groundwater, if encountered, shall
be tested for the following:
• Total petroleum hydrocarbons
(TPH) as gasoline, as diesel,
and as motor oil;
• Pesticides and herbicides;
• CAM 17 metals

Air Quality Emissions will
temporarily
increase during
Project
construction. When
compared with the
No-Build
Alternative,
operational
emissions will be
the same because
the Project will not
change regional
travel patterns or
increase capacity.

When compared
with the Build
Alternative, long-
term emissions will
be the same
because the
Project will not
change regional
travel patterns.

AMM AIR-1.1: Caltrans or the
general contractor for the project
shall submit a list of all off-road
equipment greater than 25
horsepower (hp) that would be
operated for more than 20 hours
over the entire duration of project
construction, including equipment
from subcontractors to the relevant
air district for review and
certification. The list shall include
all information necessary to ensure
the equipment meets the following
requirements:
• Equipment shall be zero
emissions or have engines
that meet or exceed either
EPA or CARB Tier 4 off-road
emission standards, or it shall
have engines that are
retrofitted with a CARB Level
3 Verified Diesel Emissions
Control Strategy (VDECS), if
one is available for the
equipment being used.

Equipment with engines that
meet Tier 4 Interim or Tier 4
Final emission standards
automatically meet this
requirement; therefore, a
VDECS would not be
required.

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Five-Way Intersection Improvements xi Final EIR/EA
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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
• Idling time of diesel-powered
construction equipment and
trucks shall be limited to no
more than two minutes. Clear
signage of this idling
restriction shall be provided
for construction workers at all
access points.

AMM AIR-1.2: Portable diesel
generators shall be prohibited.

Grid power electricity should be
used to provide power at
construction sites; or propane and
natural gas generators may be
used when grid power electricity is
not feasible.

Noise and Vibration Ambient noise
levels would
increase
temporarily during
Project
construction.

Project construction
would result in
temporary vibration
impacts. When
compared with No-
Build conditions,
increases in noise
levels would range
from zero to three
dBA during Project
operation.

Noise levels would
increase by up to
two dBA over
existing conditions.

AMM NOI-1.1: All construction
equipment shall conform to
Section 14-8.02, Noise Control, of
the latest Standard Specifications.

AMM NOI-1.2: When feasible,
noise-generating construction
activities shall be restricted to
between 7:00 a.m. and 7:00 p.m.
on weekdays, with no construction
occurring on weekends or
holidays. If work is necessary
outside of these hours, Caltrans
shall require the contractor to
implement a construction noise
monitoring program and provide
additional noise controls where
practical and feasible.

AMM NOI-1.3: Noise generating
equipment shall be located as far
as practical from sensitive
receptors when sensitive receptors
adjoin or are near the construction
Project area.

AMM NOI-1.4:"Quiet" air
compressors and other "quiet"
equipment shall be utilized where
such technology exists.

MM NOI-2.1: Avoid the use of
vibratory rollers within 25 feet of
structures. Static mode
compaction shall be used when
construction activities are less than
25 feet from structures.

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Five-Way Intersection Improvements xii Final EIR/EA
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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
MM NOI-2.2: Avoid dropping
heavy objects or equipment within
25 feet of structures.

MM NOI-2.3: Avoid the use of hoe
rams, large bulldozers, and
caisson drilling equipment within
15 feet of structures. If vibratory
rollers must be used within 25 feet
and all other equipment must be
used within 15 feet of structures,
the following measures will be
required:
• Contractor must perform
vibration monitoring, crack
monitoring and photo/video
documentation of the effected
facilities during construction.

The requirements to perform
vibration monitoring, crack
monitoring and photo/video
documentation will be
included in the Project's
construction specifications as
part of the construction
contract documents.

Energy Construction
equipment will
increase energy
consumption in the
short-term.

Compared to the
No-Build
Alternative, energy
consumption will be
slightly lower due to
improved bicycle
and pedestrian
improvements.

No effect None required
Natural
Communities
Project construction
could result in
indirect impacts to
riparian habitat
adjacent to the
proposed staging
area.

No effect AMM BIO-1.1: A spill prevention
plan shall be prepared describing
measures to be taken to minimize
the risk of fluids or other materials
used during construction (e.g., oils,
transmission and hydraulic fluids,
cement, fuel) from entering the
Napa River or contaminating
adjacent riparian areas. In addition
to a spill prevention plan, a
cleanup protocol shall be
developed before construction
begins and will be implemented in
case of a spill. The spill prevention
plan and cleanup protocol shall be

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Five-Way Intersection Improvements xiii Final EIR/EA
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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
submitted to the Caltrans Engineer
prior to construction.

AMM BIO-1.2: Stockpiling of
materials, including portable
equipment, vehicles and supplies
(e.g., chemicals), will be restricted
to the designated construction
staging areas.

Animal Species The Project would
result in tree
removal, which
could impact
migratory nesting
birds and roosting
bats.

No effect AMM BIO-2.1: The removal of any
trees or structures containing
suitable bat roosting habitat shall
be scheduled to avoid the
maternity roost season. To the
extent feasible, activities should be
restricted to the period between
August 31 and April 15.

AMM BIO-2.2: If seasonal
avoidance is not possible, within
10 days prior to the start of work, a
roosting bat survey shall be
performed by a qualified biologist
to determine if potential bat roosts
or roosting habitat is present on
the Project site or within a zone of
influence (i.e., 50 feet) and if any
avoidance measures are
necessary to avoid impacts on
bats. If roosting bats or signs of
roosting bats are observed, a
qualified biologist shall develop a
roost deterrent and/or roost
exclusion plan. The
deterrent/exclusion plan shall
include measures to avoid bats
potentially using bat tree roost
habitat within the Project limits.

Threatened and
Endangered
Species
Project construction
could result in
indirect impacts to
western pond turtle.

No effect AMM BIO-3.1: Before any ground-
disturbing activities begin, a
qualified biologist, defined as a
person who possesses, at
minimum, a bachelor's degree in
biological sciences, zoology,
botany, ecology, or another
closely-related field, and who is
familiar with western pond turtle,
shall conduct a training session for
all on-site project personnel. At a
minimum, the training will include a
description of western pond turtle
terrestrial behavior, as well as
nesting birds, roosting bats—
specifically, the pallid bat, the

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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
importance of these species, legal
protections, the measures that are
being implemented to avoid and
minimize impacts as they relate to
the Project, and the boundaries
within which work may occur.

AMM BIO-3.2: The boundaries of
the work area where natural
vegetation occurs shall be clearly
staked or otherwise delineated on
the plans to prevent workers or
equipment from inadvertently
straying from the work area. All
construction personnel, equipment,
and vehicle movement shall be
confined to designated
construction and staging areas.

AMM BIO-3.3: Plastic
monofilament netting (erosion
control matting) or similar material
shall not be used because wildlife
may become entangled or trapped
in it. Acceptable substitutes include
coconut coir matting or tackifier
hydroseeding compounds.

AMM BIO-3.4: To prevent special-
status species from entering the
construction staging area,
exclusion fencing (e.g., silt fence)
shall be constructed in strategic
locations in and around all work
areas within 100 feet of all aquatic
features. Exclusion fencing shall
be installed prior to the start of
Project-related activities and
should be placed within 10 feet of
the edge of work areas. Permittee
shall maintain the barrier
throughout all construction
activities.

A Qualified Biologist shall inspect
the area prior to fence installation.

The Project proponent shall
maintain and repair the barrier

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Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
immediately to ensure that it is
functional and without defects. The
barrier shall remain in place until
project activities in that area have
been completed and construction
equipment has been removed from
the site.

If wildlife is found along the fence,
a Qualified Biologist shall be
consulted. The Project proponent
shall avoid damage to small
mammal burrows to the maximum
extent possible during installation
of the exclusion fencing. The
Project proponent shall also
ensure that silt fencing and/or
other erosion control methods
used to prevent sediment or other
debris from passing into aquatic
habitat that is within 100 feet of
Project construction activities does
not create a barrier to special-
status species movement.

AMM BIO-3.5: Crews shall check
for wildlife under all vehicles,
equipment, materials, or otherwise
suitable locations for wildlife, such
as western pond turtle, to hide.

Workers shall inspect under
vehicles and equipment for wildlife
before vehicles and equipment are
moved or have been idle for five
minutes. If wildlife is present, they
shall be allowed to move out of the
construction area under their own
volition.

Cumulative Impacts No significant effect
with
implementation of
AMMs described
throughout the
Final EIR/EA.

No effect See AMMs listed above
Wildfire The Project is not
located within or
adjacent to a fire
hazard severity
zone.

The Project is not
located within or
adjacent to a fire
hazard severity
zone.

None required
Senate Bill
743/Induced
Demand Analysis
The Project
screens out from a
VMT analysis and
therefore would
have a less than
No effect None required

EXHIBIT A

Five-Way Intersection Improvements xvi Final EIR/EA
Napa, California July 2026
Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
significant VMT
impact.

Climate Change GHG emissions
would temporarily
increase during
Project
construction.

Project operation
would reduce GHG
emissions by
reducing vehicle
delay and
improving bicycle
and pedestrian
facilities.

No effect None required
Tribal Cultural
Resources
Potential to disturb
buried tribal cultural
resources during
construction
No effect AMM TCR-1.1: Prior to the
initiation of construction, an
agency approved archaeologist
and Native American
representative will prepare and
conduct an educational program to
instruct construction workers of the
obligation to protect and preserve
valuable resources. This program
shall be provided to all
construction workers as a field
training prior to the beginning of
ground-disturbing activities, and
shall at minimum, the training will
include a discussion of
archaeological and tribal resources
that may be encountered
(including the traditional
importance of resources such as
cultural landscapes, significant
waterways, and ethnobotanical
plants); the procedures when
working in Tribal Monitoring Areas
or near Environmentally Sensitive
Areas, if applicable; a summary of
state and federal laws and
penalties under the laws; samples
or visual aids of resources that
could be encountered in the
project vicinity; instructions
regarding the need to halt work in
the vicinity of any potential
archaeological and Native
American resources encountered;
and measures to notify their
supervisor, City of Napa Public
Works Director, and District 4

EXHIBIT A

Five-Way Intersection Improvements xvii Final EIR/EA
Napa, California July 2026
Potential Impact Build Alternative No-Build
Alternative
Avoidance, Minimization, and/or
Mitigation Measures
Office of Cultural Resources
Studies.

AMM TCR-1.2: Construction
related activities (including, but not
limited to, demolition/ excavation,
grading, and utility trenching) shall
be monitored by a Native
American tribal monitor to be
retained by Caltrans. The tribal
monitor shall have authority to halt
construction activities temporarily
in the immediate vicinity of an
unanticipated find until its
significance can be assessed by
the tribal monitor.

Monitoring within the Tribal
Monitoring Area may move to a
part-time or intermittent schedule
by mutual agreement between the
Tribes, the City of Napa and
Caltrans District 4 Office of
Cultural Resources Studies.

A summary report of the
monitoring results, including any
protective measures implemented,
shall be submitted to Caltrans
upon completion of the
construction monitoring.

S-4 COORDINATION WITH PUBLIC AND OTHER AGENCIES
Construction of the Build Alternative would not require any encroachment permits from other agencies. Coverage under the National Pollution Discharge Elimination System (NPDES) Statewide Construction General Permit will be required to address stormwater pollution issues.

EXHIBIT A

Five-Way Intersection Improvements xviii Final EIR/EA
Napa, California July 2026
Table of Contents
General Information about This Document ....................................................................... i Summary .........................................................................................................................iv Table of Contents ........................................................................................................ xviii List of Tables ..................................................................................................................xx List of Figures .................................................................................................................xx Chapter 1 Proposed Project ...................................................................................... 1

1.1 INTRODUCTION ................................................................................................... 1

1.2 PURPOSE AND NEED ......................................................................................... 1

1.3 PROJECT DESCRIPTION .................................................................................... 5

1.4 PROJECT ALTERNATIVES .................................................................................. 5

1.5 COMPARISON OF ALTERNATIVES .................................................................. 21

1.6 IDENTIFICATION OF A PREFERRED ALTERNATIVE ...................................... 22

1.7 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM FURTHER DISCUSSION PRIOR TO THE DRAFT ENVIRONMENTAL DOCUMENT ................... 23

1.8 PERMITS AND APPROVALS NEEDED ............................................................. 23 Chapter 2 Affected Environment, Environmental Consequences, and Avoidance, Minimization, and/or Mitigation Measures ..................................................................... 25

2.1 TOPICS CONSIDERED BUT DETERMINED NOT TO BE RELEVANT ............. 25 HUMAN ENVIRONMENT .............................................................................................. 27

2.2 Existing and Future Land Use ............................................................................. 27

2.3 Consistency with State, Regional, and Local Plans and Programs ..................... 30

2.4 Growth ................................................................................................................. 32

2.5 Relocations and Real Property Acquisition .......................................................... 34

2.6 Utilities/Emergency Services ............................................................................... 36

2.7 Traffic and Transportation/Pedestrian and Bicycle Facilities ............................... 38

2.8 Visual/Aesthetics ................................................................................................. 50

2.9 Cultural Resources .............................................................................................. 53 PHYSICAL ENVIRONMENT ......................................................................................... 59

2.10 Hydrology and Floodplain ................................................................................ 59

2.11 Water Quality and Stormwater Runoff .............................................................. 62

2.12 Geology/Soils/Seismic/Topography ................................................................. 68

2.13 Paleontology .................................................................................................... 71

2.14 Hazardous Waste/Materials ............................................................................. 73

2.15 Air Quality ......................................................................................................... 77

EXHIBIT A

Five-Way Intersection Improvements xix Final EIR/EA
Napa, California July 2026

2.16 Noise and Vibration .......................................................................................... 90

2.17 Energy ............................................................................................................ 113 BIOLOGICAL ENVIRONMENT ................................................................................... 116

2.18 Natural Communities ...................................................................................... 116

2.19 Animal Species .............................................................................................. 118

2.20 Threatened and Endangered Species ............................................................ 120 Chapter 3 California Environmental Quality Act (CEQA) Evaluation ..................... 126

3.1 DETERMINING SIGNIFICANCE UNDER CEQA .............................................. 126

3.2 CEQA ENVIRONMENTAL CHECKLIST ........................................................... 126

3.3 CLIMATE CHANGE........................................................................................... 164

3.4 EIR Alternatives ................................................................................................. 180 Chapter 4 Comments and Coordination ................................................................ 190

4.1 INTRODUCTION ............................................................................................... 190

4.2 NOTICE OF PREPARATION AND SCOPING PROCESS ................................ 190

4.3 CONSULTATION AND COORDINATION WITH AGENCIES AND
ORGANIZATIONS....................................................................................................... 190

4.4 DRAFT EIR/EA COMMENTS AND RESPONSES ............................................ 190 Chapter 5 List of Preparers ................................................................................... 205 Chapter 6 Distribution List ..................................................................................... 208 Chapter 7 References ........................................................................................... 210

Appendix A: Section 4(f)
Appendix B: Title VI/Non-Discrimination Policy Statement Appendix C: Summary of Relocation Benefits
Appendix D: Avoidance, Minimization, and/or Mitigation Summary Appendix E: Notice of Preparation
Appendix F: List of Technical Studies
Appendix G: Glossary of Technical Terms
Appendix H: List of Acronyms and Abbreviations
Appendix I: Consultation/Concurrence Determination
Appendix J: Draft EIR Comments

EXHIBIT A

Five-Way Intersection Improvements xx Final EIR/EA
Napa, California July 2026
List of Tables
Table 1.4-1: Project Right-of-Way Impacts .................................................................... 14 Table 1.4-2: Summary of Project Features .................................................................... 17 Table 1.5-1: Comparison of Alternatives ....................................................................... 21 Table 1.7-1: Permits and Approvals .............................................................................. 23 Table 2.1-1: Resource Topics Dismissed from Analysis ............................................... 25 Table 2.2-1: Current Land Use Projects in the Project Vicinity ...................................... 27 Table 2.7-1: Traffic Volumes Comparison ..................................................................... 42 Table 2.7-2: Roadway Segment Volume Summary....................................................... 42 Table 2.7-3: Level of Service Definitions for Signalized Intersections ........................... 43 Table 2.7-4: Existing Intersection Levels of Service ...................................................... 43 Table 2.7-5: Collision Rates (per million vehicle miles) ................................................. 44 Table 2.7-6: Future No Build LOS Conditions ............................................................... 46 Table 2.7-7: Future Build LOS Conditions ..................................................................... 47 Table 2.15-1: Air Pollutant Effects and Sources ............................................................ 77 Table 2.15-2: State and Federal Attainment Status ...................................................... 81 Table 2.15-3: Sensitive Receptors Located within 500 Feet of the Project Limits ......... 83 Table 2.15-4: Summary of Comparative Emissions Analysis ........................................ 84 Table 2.15-5: Summary of Comparative MSAT Emissions Analysis (lbs/day) .............. 86 Table 2.15-6: Uncontrolled Construction Emissions ...................................................... 87 Table 2.16-1: Noise Abatement Criteria ........................................................................ 91 Table 2.16-2: Summary of Short-Term Noise Measurements ....................................... 96 Table 2.16-3: Summary of Long-Term Noise Monitoring ............................................... 96 Table 2.16-4: Predicted Future Noise Levels .............................................................. 102 Table 2.16-5: Construction Noise Levels at 50 Feet ................................................... 105 Table 2.16-6: Vibration Source Levels of Construction Equipment ............................. 106 Table 2.16-7: Distance to Exceedance of Vibration Limit by Structure Type ............... 106 Table 2.17-1: Build Alternative Construction Energy Consumption ............................. 114 Table 2.20-1: FESA Preliminary Effect Findings ......................................................... 123 Table 3.2-1: Cumulative Projects List .......................................................................... 160 Table 3.3-1: Projected Sea-Level Rise Depths (in feet) .............................................. 176

List of Figures
Figure 1.1- 1: Regional Map ............................................................................................ 2 Figure 1.1- 2: Vicinity Map ............................................................................................... 3 Figure 1.1- 3: Aerial Photograph with Surrounding Land Uses ....................................... 4 Figure 1.4-1: Conceptual Roundabout Plan .................................................................... 7 Figure 1.4-2: Roundabout Cross-Sections ...................................................................... 8 Figure 1.4-3: SR 121 Cross-Sections .............................................................................. 9 Figure 1.4-4: Roadway Cross Sections ......................................................................... 10 Figure 1.4-5: 3D Perspective Overviews ....................................................................... 11 Figure 1.4-6: Representative Street Approaches .......................................................... 12 Figure 1.4-7: Right-of-Way Impacts............................................................................... 15 Figure 2.2-1: City of Napa 2040 General Plan Land Use Designations in the Project Area ......................................................................................................... 28

EXHIBIT A

Five-Way Intersection Improvements xxi Final EIR/EA
Napa, California July 2026
Figure 2.7-1: Existing Bicycle Facilities ......................................................................... 40 Figure 2.7-2: Existing Transit Facilities .......................................................................... 41 Figure 2.7-3: Potential Detour Roadways ..................................................................... 51 Figure 2.10-1: FEMA Flood Map ................................................................................... 60 Figure 2.15-1: Sensitive Receptors Located Near the Project ....................................... 82 Figure 2.16-1: Noise Levels of Common Activities ........................................................ 92 Figure 2.16-2: Noise Measurement Locations North of Third Street ............................. 94 Figure 2.16-3: Noise Measurement Locations South of Third Street ............................. 95 Figure 2.16-4: Receptor Locations Between Second Street and Third Street ............... 97 Figure 2.16-5: Receptor Locations Near the Five-Way Intersection .............................. 98 Figure 2.16-6: Receptor Locations Along Third Street .................................................. 99 Figure 2.16-7: Receptor Locations South of the Five-Way Intersection ...................... 100 Figure 2.16-8: Receptor Locations Between Hennessy Drive and Fairview Drive ...... 101 Figure 2.16-9: Evaluated Barrier 1 Location ................................................................ 104 Figure 2.16-10: Identified Historical Buildings in the Project Area ............................... 108 Figure 2.16-11: Identified Older Residential Buildings within 20 Feet of the Project Limits ................................................................................................. 109 Figure 2.16-12: Identified Commercial Buildings within 15 feet of the Project Limits .. 110 Figure 3.3-1: U.S. 2022 Greenhouse Gas Emissions ................................................. 167 Figure 3.3-2: California 2021 Greenhouse Gas Emissions by Economic Sector ......... 167 Figure 3.3-3: Change in California GDP, Population, and GHG Emissions since 2000 ....................................................................................................... 168 Figure 3.3-4: Area Projected to be Affected by Sea Level Rise .................................. 178

EXHIBIT A

Five-Way Intersection Improvements 1 Final EIR/EA
Napa, California July 2026
Chapter 1 Proposed Project

1.1 INTRODUCTION
The California Department of Transportation (Caltrans), as assigned by the Federal Highway Administration (FHWA), is the lead agency under the National Environmental Policy Act (NEPA). The City of Napa is the lead agency under the California Environmental Quality Act (CEQA).

The City of Napa proposes to convert the existing intersection of Silverado Trail (State Route 121), Third Street, Coombsville Road, and East Avenue to two, single-lane roundabouts (Project). The Project intersection is located in southeast Napa at post mile

7.35. Regional and vicinity maps are shown in Figure 1.1- 1 and Figure 1.1- 2, respectively. An aerial photograph of the Project site and the surrounding land use is shown in Figure 1.1- 3.

This Project is included in the 2025 Federal Statewide Transportation Improvement Program (FSTIP)1 and the Metropolitan Transportation Commission’s (MTC) Regional Transportation Plan (RTP), Plan Bay Area 2050.2

1.2 PURPOSE AND NEED

1.2.1 Purpose
The purpose of the Project is to improve the operations of the intersection that will result in reduced driver delay, reduced congestion, and, therefore, an overall improvement to intersection operations. Additionally, the purpose of the Project is to improve the safety and accessibility for all users of the intersection. The secondary objectives of this Project are to improve bicycle and pedestrian facilities at the intersection as well as meet ADA requirements.

1.2.2 Need
The Project intersection needs geometric improvements to improve the operations, efficiency, and capacity of the intersection. In addition, safety improvements are needed to reduce collisions through the SR 121 corridor, which is ranked among the highest injury corridors within the City of Napa per the City’s Local Roadway Safety Plan (adopted September 6, 2022). Data was obtained and analyzed from both the Caltrans Traffic Accident Surveillance and Analysis System (TASAS) and the City of Napa Police Department for the latest 5-year period in the Project area along SR 121. There were ten reported collisions within the Project area, which resulted in a higher than statewide average rate for similar facilities.

1 TIP ID: NAP170009
2 RTP ID: 21-T07-056

EXHIBIT A

EXHIBIT A
Coombsville Road
Coombsville Road
Silverado Trail
Silverado Trail
Terrace Drive
Shurtleﬀ Avenue
3rd Street
2nd Street
East Avenue
Soscol Avenue
1st Street
Laurel Street
Jeﬀerson Street
Coombs Street
Montecito Boulevar d
Napa RiverNapa River
Napa River
Napa Creek
U.P .R.R.

U.P .R.R. Silverado Trail
Silverado Trail
Terrac
e Drive
ShurtleﬀAvenue
3rd Street
2nd Street
East Avenue
Soscol Avenue
1st Street
Laurel Street
Jeﬀerson Street
Coombs Street
MontecitoB oulevar d
Napa RiverNapa River
Napa River
NapaCre
ek
U.P .R.R.

U.P .R.R.
121
121
Project Boundary
Staging Area
Base Map: ESRI, ArcGIS
0 200 800 1,200 1,600 Feet
VICINITY MAP FIGURE 1.1-2

EXHIBIT A

Five-Way Intersection Improvements 5 Final EIR/EA
Napa, California July 2026
Traffic studies conducted by the City of Napa have shown that the intersection has operated at a Level of Service (LOS) D since at least the year 2000. Although the intersection is already operating at an unacceptable LOS,3 operations will continue to deteriorate due to the continued growth of the area and continued increase in vehicular demand on this intersection, as documented in the Napa-Solano Travel Demand Model.

The existing intersection has limited and substandard pedestrian facilities,4 including long, skewed crosswalks and narrow sidewalks, that increase pedestrian exposure to vehicle conflicts throughout the five-legged intersection. Existing pedestrian facilities do not meet current ADA standards. There are discontinuous sidewalks on the northwest and southwest sides of SR 121 that extend for approximately 50 feet and 200 feet, but no other sidewalks exist at the intersection. The existing intersection also does not provide bicycle facilities, resulting in a disconnect in the existing bicycle facilities along Third Street, Coombsville Road, and East Avenue.

1.3 PROJECT DESCRIPTION
This section describes the proposed action and the Project alternatives developed to meet the purpose and need of the Project, while avoiding or minimizing environmental impacts. The alternatives are the “Build Alternative” and the “No-Build Alternative.” The Project is located in Napa County on State Route 121 at its intersection with Third Street, Coombsville Road, and East Avenue. The Project proposes to improve the intersection by constructing two, modern, single-lane roundabouts with curb, gutter, ramps, sidewalk, streetlights, and storm drain improvements. The proposed Project would ease traffic congestion by introducing a traffic-calming circulation pattern, improving community connectivity in the Project area, and improving pedestrian and bicycle safety within and adjacent to the intersection. Local circulation and access would largely remain unchanged. The Project intersection geometrics and pedestrian crossings are consistent with the National Cooperative Highway Research Program (NCHRP) Report 672 entitled “Roundabouts: An Information Guide, 2nd Edition” (Guide).

1.4 PROJECT ALTERNATIVES

1.4.1 Build Alternative

1.4.1.1 SR 121/Third Street/Coombsville Road/East Avenue Intersection A double roundabout with four legs on the northerly roundabout and three legs on the southerly roundabout would accommodate the Design Year traffic volumes. Retaining walls will be required to minimize adjacent property impacts along Coombsville Road and East Avenue. Along Coombsville Road, a retaining wall minimizes grading impacts that would otherwise require removal of multiple mature trees. Along East Avenue, the retaining wall minimizes encroachment onto the parcel at the northeast corner of the intersection with SR 121 to maintain economic viability of the commercial parcel. Due to

3 The City’s LOS standard for the intersection is mid-LOS E which is exceeded under existing conditions. 4 Substandard pedestrian facilities include discontinuous sidewalks and lack of ADA compliance.

EXHIBIT A

Five-Way Intersection Improvements 6 Final EIR/EA
Napa, California July 2026
the steep entry grades coming into/out of East Avenue and Coombsville Road, the new roundabout intersections will largely be in fill in order to flatten the roadway grade on the entry/exits. Minor regrading on approaches where the Project conforms to existing roadways will be required, but would be a maximum excavation of three to five feet. A conceptual plan is shown in Figure 1.4-1, cross-sections are shown in Figure 1.4-2 through Figure 1.4-4, and 3D renderings are shown in Figure 1.4-5 and Figure 1.4-6.

The landscape and aesthetic treatments shown in the 3D renderings are conceptual and the final design will be determined during future design phases of the Project.

1.4.1.2 Pedestrian and Bicycle Safety
A 10-foot wide shared-use path will be provided throughout the new roundabout(s) buffered by at least 2 feet of landscaping from the roadway. The shared-use path conveys both pedestrian and bicycle traffic through the intersection. Ramps will provide access to and from the shared-use path for bicyclists. Each leg of the two roundabouts will conform to existing bikeways as appropriate. In the existing condition, there are no dedicated bicycle facilities on SR 121 north of the Project (though bicyclists are permitted on the roadway). There are Class II Bicycle Lanes5 on SR 121 south of the Project. Northbound bicyclists on SR 121 approaching the Project will have an option to either merge from the bicycle lane into the travel lane and navigate the intersection using the circulating lanes or use the provided bike ramp to access the shared-use path and navigate using marked crossings; southbound bicyclists leaving the Project will re- enter the bicycle lane using either the provided bike ramp, if they are on the shared-use path, or by merging from the travel lane, if they are in the roadway.

Pedestrians will travel through the Project area using a combination of sidewalks, the new shared-use path, and marked crossings. Where realignment of roadways is occurring for the new roundabout approaches, existing sidewalks will be replaced to follow the new roadway edge. Marked pedestrian crossings are set back a minimum of one car length away from the circulatory roadway. This allows approaching drivers to yield to pedestrians or bicyclists in the crosswalk and then pull forward to yield to oncoming drivers in the circulating lane, and exiting drivers to clear the circulating lane before yielding to a pedestrian or bicyclist. Pedestrian refuges at the splitter islands are at least 6 feet wide (consistent with the NCHRP Guide). These two-stage crossings reduce the amount of sustained time a pedestrian is in potential conflict with motorized vehicles by limiting the length of each crossing and limiting each crossing to one direction of vehicle travel at a time. All pedestrian curb ramps would be ADA compliant.

1.4.1.3 Reduced Speed and Collision Potential
The geometric design of roundabouts typically requires drivers to reduce speed in the intersection to 15-25 mph. At signalized intersections, drivers are typically able to travel through the intersection at speeds higher than posted limits due to the lack of geometric constraints. Because of these reduced travel speeds through the intersection and expected reduction in crashes, the Project is likely to eliminate the most severe crash types.

5 Class II Bike Lanes provide an exclusive space for bicyclists in the roadway and are established by painting lines and symbols on the roadway surface.

EXHIBIT A
0 25 50 100 200 Feet
CONCEPTUAL ROUNDABOUT PLAN FIGURE 1.4-1

EXHIBIT A

SOUTH ROUNDABOUT

NORTH ROUNDABOUT
ROUNDABOUT CROSS-SECTIONS FIGURE 1.4-2

EXHIBIT A
ROUTE 121 BETWEEN ROUNDABOUTS
ROUTE 121 NORTH OF ROUNDABOUT ROUTE 121 SOUTH OF ROUNDABOUT SR 121 CROSS-SECTIONS FIGURE 1.4-3

EXHIBIT A
3RD STREET

COOMBSVILLE ROAD EAST AVENUE
ROADWAY CROSS-SECTIONS FIGURE 1.4-4

EXHIBIT A
Source: GHD, Inc.

NORTH ROUNDABOUT SOUTH ROUNDABOUT
3D PERSPECTIVE OVERVIEWS FIGURE 1.4-5

EXHIBIT A

THIRD STREET APPROACH
Source: GHD Inc. SOUTHBOUND SR 121 APPROACH AT THIRD STREET REPRESENTATIVE STREET APPROACHES FIGURE 1.4-6

EXHIBIT A

Five-Way Intersection Improvements 13 Final EIR/EA
Napa, California July 2026

1.4.1.4 Structures
Retaining walls will be required to minimize adjacent property impacts along Coombsville Road and East Avenue, type selection will be completed later this phase to finalize type and size of wall, however every effort will be made to minimize footings (currently anticipated to be approximately three to five feet deep) to reduce potential environmental and right of way impacts.

A short cut style retaining wall (approximately four to six feet tall and 100 feet long) is required along a portion of the northern side of Coombsville Road in order construct the new shared use path and roundabout approach deflection while not encroaching into a large slope within a private parcel. At this time, it is anticipated that a spread footing style would be utilized to minimize depth of disturbance (approximately two feet below grade).

Another short fill style retaining wall (approximately 12 to 14 feet maximum height and 80 feet long) is required along a portion of the northern side of East Avenue along the car dealership parcel in order to construct the new shared use path and roundabout approach deflection while not further impacting the car dealership parking lot. At this time, it is anticipated that a spread footing style would be utilized to minimize depth of disturbance (approximately four feet below grade).

1.4.1.5 Right of Way
Four commercial properties have driveway access points within the Project area that will be replaced/adjusted as needed. Business access will be provided throughout the construction process in coordination with business property owners.

One vacant parcel and one residential property will require full/major acquisition in order to construct the new roundabouts and minimize the overall impacts within the Project vicinity.

In addition, minor frontage impacts to adjacent parcels may be required in order to conform the roundabouts and/or shared use path to existing facilities. These minor frontage impacts include driveway conforms or realignments. Work would primarily occur through a Temporary Construction Easement (TCE) but may require some minor right-of-way acquisition so that the City will own the sidewalks to facilitate maintenance while Caltrans will own the highway up to the back edge of the curb on both sides of SR 121. The Project’s potential right-of-way impacts are summarized in Table 1.4-1 and shown in Figure 1.4-7. For private residences, the addresses are included and for commercial properties, the business names are identified.

EXHIBIT A

Five-Way Intersection Improvements 14 Final EIR/EA
Napa, California July 2026
Table 1.4-1: Project Right-of-Way Impacts

Impact Type Full Property
(Assessor’s Parcel Number)
Partial Property
(Assessor’s Parcel Number)
Temporary
Easement

006-147-003 (820 Juarez Street)
006-147-005 (802 Juarez Street)
006-147-008 (El Rancho Grande)
006-148-010 (Napa Tire & Wheels)
006-148-012 (commercial center)
006-151-010 (Posh Motors)
006-152-001 (Napa Marble & Granite
Works)
006-152-002 (1010 East Avenue)
006-211-010 (36 Coombsville Road)
Permanent
Acquisition
006-147-004 (801 Silverado Trail) 006-147-003 (820 Juarez Street) 006-147-008 (El Rancho Grande)
006-148-010 (Napa Tire & Wheels)
006-148-012 (commercial center)
006-151-010 (Posh Motors)
006-152-001 (Napa Marble & Granite
Works)
006-152-002 (1010 East Avenue)
006-211-010 (36 Coombsville Road)

1.4.1.6 Utilities
Due to the grading that will be required to construct the new roundabouts, relocation of the City water transmission line that runs from 3rd Street as well as up to six joint utility poles will need to be relocated or undergrounded. All are anticipated to occur within existing or proposed right of way. In addition, adjustment of utility vaults to match the final pavement surface elevation would be required along SR 121 and some fill materials may be required depending on cover and new conform grading requirements.

All other existing utilities would be protected in place.

EXHIBIT A
LEGEND:

ACQUISITION

TEMPORARY CONSTRUCTION EASEMENT

PROPOSED RIGHT OF WAY LINE

PARCEL LINE
EAST Ave
COOMBSVILLE Rd
THIRD St
ROUTE 121
ROUTE 121

STATE R/W

STATE R/W
JUAREZ St
TAYLOR St1
2 3
4 5
7 8
9 10
6 CITY R/W

CITY R/W

CITY R/W
PARCEL

NUMBER APN ADDRESS

ROW ACQUISTION TYPE

PERMANENT
(SF)

TEMPORARY

CONSTRUCTION

EASEMENT (SF)
1 006-147-005 802 JUAREZ ST 540
2 006-147-004 801 SILVERADO TR 8240
3 006-147-003 820 JUAREZ ST 2140 900
4 006-147-008 891 SILVERADO TR 120 440
5 006-151-010 800 SILVERADO TR 1020 1370
6 006-148-012
325, 333, 341, 343
3RD ST 220 1240
7 006-148-010 713 SILVERADO TR 2630 2150
8 006-211-010 36 COOMBSVILLE RD 12160 2370
9 006-152-001 9 COOMBSVILLE RD 140 295
10 006-152-002 1010 EAST AVE 30 1710
Total 26700 11015
0 25 50 100 200 Feet
Source: GHD, December 17, 2024.

RIGHT-OF-WAY IMPACTS FIGURE 1.4-7

EXHIBIT A

Five-Way Intersection Improvements 16 Final EIR/EA
Napa, California July 2026

1.4.1.7 Construction
Construction is anticipated to begin in 2027 and to last approximately 18 months.

Construction will involve the use of conventional construction equipment and staging is anticipated to occur within the paved area of the Project limits, roadway shoulders, and a paved City parking lot on Third Street west of the Project site (if needed). Before construction, the Caltrans resident engineer and the contractor will identify any necessary lane closures and use proper traffic control devices throughout the duration of the Project per Caltrans Standard Specifications and Standard Plans. During construction, at least one travel lane in each direction of SR 121 will be kept open during peak hours, as will Third Street, Coombsville Road, and East Avenue. Closures, if necessary, will occur only at night. Approval of a Traffic Management Plan (TMP) will also provide adequate traffic access for all businesses and residences.

Construction activities may potentially include detours. Detour routes may include the use of local streets such as Hennessey Drive, Soscol Avenue, First Street, Juarez Street, and Taylor Street. Advance notification of construction work will be provided to the community. Prenotification will be provided at Soscol Avenue and First Street encouraging drivers to take alternate routes, which may lower traffic volumes in the Project area during construction. Cyclists will be required to share the road with vehicles during some construction stages and signing and striping will be provided to warn drivers. Pedestrian detours will be accommodated for locations where existing facilities occur.

Noise associated with construction will be controlled by 2023 Caltrans Standard Specification Section 14-8.02, “Noise Control." Night work may be necessary for a limited number of working days to allow closures and one-way flagging to accommodate reconstruction of the roadway. Trucks and buses will be accommodated through the Project site during all stages of construction.

1.4.1.8 Depth of Disturbance
Excavation would be required throughout the Project in order to construct utility relocations (approximately three to six feet deep depending on utility), lighting, landscaping and drainage facilities, which require trenching, placement of pipe, drainage structures, landscaping, irrigation, and backfill to a depth of six feet. A maximum excavation depth of 10 feet may be required to install foundations for retaining walls along the Coombsville Road and East Avenue legs.

1.4.1.9 Project Features
The Project contains a number of standardized project components which are employed on most, if not all of Caltrans projects and were not developed in response to any specific environmental impact resulting from the Project. These components are referenced as Project Features in Chapter 3 as they pertain to different environmental resources, and are separated out from avoidance and minimization measures (AMMs) and Mitigation Measures (MMs), which directly relate to the impacts resulting from the Project.

EXHIBIT A

Five-Way Intersection Improvements 17 Final EIR/EA
Napa, California July 2026
Table 1.4-2 lists the Project Features that would be implemented by Caltrans and the construction contractor to reduce or avoid potential impacts to the human and natural environment.

Table 1.4-2: Summary of Project Features
Resource Area Reference Project Feature
Utilities/Emergency
Services
PF UTI-1.1 Trash Management. All food-related trash items such as wrappers, cans, bottles, and food scraps would be disposed of in closed containers and removed at least once daily from the Project limits. A Trash Reduction System would also be developed and implemented per Caltrans NPDES Permit and San Francisco RWQCB Cease and Desist Order.

Utilities/Emergency
Services
PF UTI-1.2 Notify Utility Owners of Construction Schedule. All affected utility companies would be notified of construction schedules for Project work so that they can relocate or provide special instructions for utility protection if needed, and minimize disruption of utility service.

Traffic and
Transportation
PF TRA-1.1 Traffic Management Plan (TMP). A TMP will be prepared in the design phase and implemented in construction. The TMP will provide detour routes and notification to emergency and medical providers in the Project area of alternative access routes during temporary closures.

Visual/Aesthetics PF VIS-1.1 Preserve Existing Trees and Vegetation. The Project shall be designed to avoid loss or damage of existing trees and other vegetation, to the maximum extent feasible.

Visual/Aesthetics PF VIS-1.2 Tree Replacement. Depending on the extent of tree removal, replacement planting, irrigation, and plant
establishment shall be provided within the Project limits where safety and maintenance requirements can be met.

Cultural Resources PF CULT-1.1 Unanticipated Discoveries. In the event that archaeological resources (sites, features, or artifacts) or Tribal Cultural Resources (TCRs) (as defined by the consulting Tribes and CEQA) are exposed during construction activities, all
construction work occurring within 60 feet of the find shall immediately stop until a qualified archaeologist, that meets the Secretary of the Interior Professional Qualifications for Archaeology, can evaluate the significance of the find in consultation with the Tribe to determine whether or not additional study is warranted. Additional archaeological survey will be needed if project limits are extended beyond the present survey limits.

If any TCRs are found during construction, a Professionally Qualified Staff archaeologist shall assess the find. The Office of Cultural Resource Studies will notify local consulting Tribes if the resource is determined to be a TCR and consult with the contractor and the Tribe to determine whether the
resources can be avoided by the Project. If the TCR cannot be avoided, then further consultation efforts with the Tribes would be necessary to determine its treatment.

Cultural Resources PF CULT-1.2 Human Remains. If human remains are discovered during ground-disturbing activities, construction-related activities would be halted in any area or nearby area suspected to overlie remains immediately. The Caltrans’ Office of Cultural Resource Studies and the City of Napa Public Works Director shall be immediately notified. Caltrans’ Cultural Resources Studies Office will contact the County Coroner. If the remains

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Five-Way Intersection Improvements 18 Final EIR/EA
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Resource Area Reference Project Feature
are thought by the coroner to be Native American, the
coroner will notify the Native American Heritage Commission (NAHC), who, pursuant to PRC Section 5097.98, will then notify the Most Likely Descendent (MLD). Caltrans, District 4, Cultural Resources Studies Office and the City of Napa
Public Works Director will work with the Most Likely
Descendent on the respectful treatment and disposition of the remains. Further provisions of PRC 5097.98 are to be
followed as applicable.

Water Quality and
Stormwater Runoff
PF WQ-1.1 Water Quality BMPs. Although long-term water quality effects of the Project would not be substantial, the design of the Project includes Best Management Practices (BMPs)
such as site design, permanent erosion control, drainage facilities, source control measures, and treatment measures to reduce the pollutant component of stormwater runoff, as required by the Caltrans National Pollution Discharge
Elimination System (NPDES) permit. In addition to the
requirements of the NPDES permit, compliance with the
requirements of the Caltrans Stormwater Management Plan (SWMP) is also required throughout implementation of the Project. The SWMP describes the programs to reduce the
discharge of pollutants associated with the stormwater
drainage systems and describes how Caltrans will comply with the provisions of the NPDES permit.

Hazardous
Water/Materials
PF HM-1.1 Aerially Deposited Lead Work Plan. As part of Project development, a soil investigation will be conducted to
determine whether aerially-deposited lead (ADL) has affected soils that will be excavated as part of the proposed Project.

The investigation for ADL will be performed in accordance with Caltrans’ Lead Testing Guidance Procedure. The
analytical results will be compared against applicable
hazardous waste criteria. Based on analytical results, the investigation will provide recommendations regarding
management and disposal of affected soils in the Project area, including the reuse potential of ADL-affected soil during Project development. The provisions of a variance granted to Caltrans by the California Department of Toxic Substances Control on September 22, 2000 (or any subsequent variance in effect when the Project is constructed) regarding aerially- deposited lead will be followed.

Hazardous
Waste/Materials
PF HM-1.2 Hazardous Material. If at any point during construction stained or odoriferous soils are encountered, or unanticipated asbestos, work shall immediately stop in the area of the discovery and the Caltrans Engineer will be notified. Any potentially contaminated soils shall be stockpiled separately on plastic sheeting. The stockpiles shall then be sampled for the above-mentioned analytes and characterized for special handling and/or disposal.

Hazardous
Waste/Materials
PF HM-1.3 Treated Wood Disposal. Treated wood shall be handled properly in accordance with applicable Caltrans guidelines and if warranted, will require special removal, handling, and disposal.

Air Quality PF AIR-1.1 Maintaining Construction Equipment and Vehicles. All construction equipment shall be maintained and properly

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Five-Way Intersection Improvements 19 Final EIR/EA
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Resource Area Reference Project Feature
tuned in accordance with manufacturer’s specifications. All equipment shall be checked by a certified mechanic and
determined to be running in proper condition prior to
operation on the Project.

Air Quality PF AIR-1.2 Contractor Air Quality Compliance. The construction contractor must comply with the Bay Area Air District (Air District) published CEQA Air Quality Guidelines Best
Management Practices (BMPs) as outlined below:
• All haul trucks transporting soil, sand, or other loose material off-site shall be covered.
• On-site dirt piles or other stockpiled PM shall be
covered, wind breaks installed, and water and/or soil
stabilizers employed to reduce wind-blown dust
emissions. The use of approved nontoxic soil
stabilizers shall be incorporated according to
manufacturers’ specifications to all inactive
construction areas.
• All visible mud or dirt track-out onto adjacent public roads shall be removed using wet power vacuum
street sweepers at least once per day. Dry power
sweeping should only be performed in conjunction
with thorough watering of the subject roads.
• All vehicle speeds on unpaved roads and surfaces
shall be limited to 15 mph.
• All roadway, driveway, and sidewalk paving shall be
completed as soon as possible. Building pads shall
be paved as soon as possible after grading.
• All construction sites shall provide a posted sign
visible to the public with the telephone number and
person to contact at the lead agency regarding dust
complaints. The recommended response time for
corrective action shall be within 48 hours. The Air
District’s Complaint Line (1-800-334-6367) shall also
be included on posted signs to ensure compliance
with applicable regulations.
• All excavation, grading, and/or demolition activities shall be suspended when average wind speeds
exceed 20 mph.
• Wind breaks (e.g., trees, fences) shall be installed on the windward side(s) of actively disturbed areas of
construction. Wind breaks should have at maximum
50 percent air porosity.
• Vegetative ground cover (e.g., fast-germinating
native grass seed) shall be planted in disturbed
areas as soon as possible and watered appropriately
until vegetation is established.
• The simultaneous occurrence of excavation, grading,
and ground-disturbing construction activities on the
same area at any one time shall be limited. Activities
shall be phased to reduce the amount of disturbed
surfaces at any one time.
• All transfer processes involving a free fall of soil or other PM shall be operated in such a manner as to
minimize the free fall distance and fugitive dust
emissions.
• All trucks and equipment, including their tires, shall be washed off before leaving the site.

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Five-Way Intersection Improvements 20 Final EIR/EA
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Resource Area Reference Project Feature
• Site accesses to a distance of 100 feet from the
paved road shall be treated with a 6-to 12-inch
compacted layer of wood chips, mulch, or gravel.
• Sandbags or other erosion control measures shall be
installed to prevent silt runoff to public roadways from sites with a slope greater than one percent.
• Open burning shall be prohibited at the project site.

No open burning of vegetative waste (natural plant
growth wastes) or other legal or illegal burn materials (e.g., trash, demolition debris) may be conducted at
the project site. Vegetative wastes shall be chipped
or delivered to waste-to-energy facilities (permitted
biomass facilities), mulched, composted, or used for
firewood. It is unlawful to haul waste materials off-site for disposal by open burning.
• The primary contractor shall be responsible for
ensuring that all construction equipment is properly
tuned and maintained before and for the duration of
on-site operation.
• Where accessible, existing power sources (e.g.,
power poles) or clean-fuel generators shall be used
rather than temporary power generators.
• A traffic plan shall be developed to minimize traffic flow interference from construction activities. The
plan may include advance public notice of routing,
use of public transportation, and satellite parking
areas with a shuttle service. Operations that affect
traffic shall be scheduled for off-peak hours.

Obstruction of through-traffic lanes shall be
minimized. A flag person shall be provided to guide
traffic properly and ensure safety at construction
sites.
• Applicable mitigation measures shall be required at
the time grading permits are issued.

Noise and Vibration PF NOI-1.1 Idling of Combustion Engines. Unnecessary idling of internal combustion engines within 100 feet of residences shall be strictly prohibited.

Noise and Vibration PF NOI-1.2 Maintaining Internal Combustion Engines. All internal combustion engine driven equipment shall be equipped with manufacturer recommended intake and exhaust mufflers that are in good condition and appropriate for the equipment.

Animal Species PF BIO-1.1 Migratory Birds. Project activities shall be scheduled to avoid the nesting bird season. For project planning purposes, the nesting bird season in the San Francisco Bay Area for birds protected under the MBTA is often identified by
regulatory agencies as February 1 through August 31.

If seasonal avoidance is not possible, within three days prior to the start of work, a nesting bird survey shall be performed by a qualified biologist on the project site and within a zone of influence (i.e., 100 feet for non-raptor migratory birds and 300 feet for raptors). All nest avoidance requirements of the MBTA and CFGC shall be observed (e.g., establishing
appropriate protection buffers around active nests until young have fledged). A qualified biologist shall resurvey the Project site if a halt in Project activities of three days or more occurs.

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Resource Area Reference Project Feature
All nests identified during pre-construction surveys shall be determined “inactive” by a qualified biologist prior to removal.

If seasonal avoidance is not possible and nesting birds are present, a qualified biologist shall establish temporary buffers around the nest. Project activities shall not occur within the buffer areas until the nest has fledged or has otherwise become inactive. The qualified biologist shall monitor all identified nesting birds or roosting bats within the survey area long enough to determine whether project activities will result in observable signs of disturbance. Buffers may need to be adjusted to a greater distance if needed to ensure
disturbance does not occur as a result of Project-related activities. Conversely, buffer size may be decreased in consultation with CDFW if project-related activities do not result in disturbance.

1.4.2 No Build Alternative
The No Build Alternative leaves the existing lane geometrics and intersection controls in place, without a roundabout. Under existing conditions, the intersection of SR 121/Third Street/Coombsville Road/East Avenue remains signalized. This alternative does not meet the purpose and need for the Project to improve intersection operations.

1.5 COMPARISON OF ALTERNATIVES
This section highlights the differences between the Build Alternative and the No Build Alternative. Key differences are shown in Table 1.5-1.

Table 1.5-1: Comparison of Alternatives
Category Build Alternative No Build Alternative
Summary of Vehicular
Improvements
Replacing the existing
intersection with two
roundabouts to ease traffic
congestion and introduce a
traffic-calming circulation
pattern.

No improvements
Key Bicycle and
Pedestrian Improvements
Construct a new 10-foot
shared use path and
sidewalks through the
roundabouts with marked
crossings and pedestrian
refuge islands.

No improvements
Ability to Meet Purpose
and Need
Meets the purpose and
need
Does not meet the purpose
and need
Cost $27.15 million $0

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Five-Way Intersection Improvements 22 Final EIR/EA
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Category Build Alternative No Build Alternative
Changes in Traffic
Circulation Pattern
Replacing the existing
intersection with two
roundabouts.

No changes
Effect on Congestion and
Delay
Reduction in traffic
congestion and delay.

Congestion will worsen
over time as planned
growth continues.

Business Relocations None None
Residential Relocations Full acquisition of one
residential parcel
None
Change in Noise Levels
Compared to Existing
Conditions
0 to +4 dBA 0 to +2 dBA
Change in Noise Levels
Compared to No Build
Conditions
0 to +3 dBA --
Visual Impacts Moderate to moderately
low level of change.

None
Impacts to Sensitive
Habitats
Potential impacts to
riparian habitat but will be
avoided/minimized.

None
Impacts to Threatened and
Endangered Species
Potential impacts to
western pond turtles,
nesting birds, and roosting
bats but will be avoided/
minimized.

None
Duration of Construction Approximately 18 months None
Construction Impacts Noise, vibration, and dust
may be substantial but will
be avoided/minimized.

None

1.6 IDENTIFICATION OF A PREFERRED ALTERNATIVE
After comparing and weighing the benefits and impacts of all feasible alternatives, the Project Development Team identified the Build Alternative as the preferred alternative on March 3, 2026. This decision was made after considering all comments from the public and internal Project Development Team. In accordance with CEQA, the City has certified that the Project complies with CEQA and has prepared findings for all significant impacts identified. A Statement of Overriding Considerations for impacts that will not be mitigated below a level of significance has been prepared and the City certifies that the findings and Statement of Overriding Considerations has been considered prior to project approval. A Notice of Determination will be filed with the State Clearinghouse identifying the significant impacts of the project, mitigation measures included as conditions of project approval, findings that have been made, and that a Statement of Overriding Considerations was adopted. Similarly, Caltrans, as assigned by the FHWA, determined that the NEPA action does not significantly impact the environment, and has issued a Finding of No Significant Impact (FONSI). An NOA

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Five-Way Intersection Improvements 23 Final EIR/EA
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of the FONSI will be filed with the State Clearinghouse along with a Notice of Statute of Limitations on the Federal Register by FHWA.

1.7 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM

FURTHER DISCUSSION PRIOR TO THE DRAFT ENVIRONMENTAL

DOCUMENT
Through the Project Initiation Document (PID) phase, three build alternatives were identified. However, during initial review of the build alternatives presented in the PID, and considering geometric updates that would be required to align with current roundabout design guidance, two alternatives were identified as having excessive impacts for the benefits obtained.

Alternative 6 proposed to replace the existing intersection with a five-legged multi-lane roundabout. In addition to impacting the residential parcel at 801 Silverado Trail, which is impacted by the Build Alternative, Alternative 6 would have also impacted two additional properties on the northeast side of Coombsville Road, including the Napa Marble & Granite Works property. Design refinements to align with updated standards related to entry geometry would have also resulted in impacts to the potentially eligible historic Tulocay Cemetery located on Coombsville Road, which would subsequently require additional Section 4(f) review and a historic resource evaluation. Community members raised concerns about Alternative 6 related to impacts to the Napa Marble & Granite Works business and operational performance of the roundabout for 2040 and beyond.

Alternative 8 proposed to replace the existing intersection with two, single-lane roundabouts. Unlike the Build Alternative, this alternative proposed Third Street to be included in the southern roundabout along with Coombsville Road and SR 121. The northern roundabout was proposed to be a three-legged roundabout with SR 121 and East Avenue. While this alternative avoided the full impact to the 801 Silverado Trail parcel, it required full acquisition of four commercial properties in the Project area and would have impacted the state-owned Napa Valley Expo fairgrounds property.

Community members also raised concerns about operational performance of Alternative 8 for 2040 and beyond.

As such, Alternatives 6 and 8 were rejected prior to the initiation of the Project Approval and Environmental Document (PA&ED) phase.

1.8 PERMITS AND APPROVALS NEEDED
The following permits, licenses, agreements, and certifications (PLACs) are required for project construction:

Table 1.7-1: Permits and Approvals
Agency PLAC Status
City of Napa Demolition permit Application to be submitted during final design.

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Five-Way Intersection Improvements 24 Final EIR/EA
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Agency PLAC Status
City of Napa Grading permit Application to be submitted during final design.

City of Napa Tree removal permit Application to be submitted during final design.

State Historic Preservation
Officer
Memorandum of
Agreement (MOA)
MOA was fully executed
between SHPO and
Caltrans on June 25, 2026.

Federal Highway
Administration (FHWA)
Air Quality Conformity
Determination
The Project was found not
to be a project of air quality
concern by MTC’s Air
Quality Conformity Task
Force on March 27, 2025.

FHWA approved the
project level conformity
determination on June 4,
2026.

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Five-Way Intersection Improvements 25 Final EIR/EA
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Chapter 2 Affected Environment,
Environmental Consequences,
and Avoidance, Minimization,
and/or Mitigation Measures

2.1 TOPICS CONSIDERED BUT DETERMINED NOT TO BE RELEVANT As part of the scoping and environmental analysis carried out for the project, the following environmental issues were considered but no adverse impacts were identified.

As a result, there is no further discussion about these issues in this document.

Table 2.1-1: Resource Topics Dismissed from Analysis
Resource Rationale for Dismissal
Coastal Zone There would be no effects to coastal resources because the Project is not located within the coastal zone.6
Wild and Scenic
Rivers
There would be no effects to wild and scenic rivers because the Project is not located near a designated wild and scenic river. The nearest river with this designation, the Lower American River, is over 45 miles from the Project site.7

Parks and
Recreational
Facilities
The Project would not acquire any lands from or require any temporary construction easements from parks and recreational facilities. There are no existing parks located within or adjacent to the Project limits. The nearest park to the Project limits is Fairview Park, located approximately 1,000 feet southeast of the Project. The Project would not affect Fairview Park or any other parks or recreational facilities.

While the adjacent Napa Valley Expo is a publicly-owned fairgrounds, it functions primarily for commercial purposes (fairs, concerts, etc.) rather than as a park or recreation area.

Farmlands
There would be no effects to farmlands because the Project is not located within or near any Prime Farmland, Unique Farmland, Farmland of Statewide Importance, or properties subject to a Williamson Act contract. The Project site and surrounding vicinity are designated as Urban and Built-Up Land.8, 9

Timberlands
There would be no effects to timberlands because the Project site and surrounding vicinity do not contain any lands zoned as forest land, timberland, or timberland production. The Project would not convert any existing forest or timberland to non-forest use.

6 California Coastal Commission. “Maps. Coastal Zone Boundary”. Accessed January 29, 2025. https://www.coastal.ca.gov/maps/czb/
7 National Wild and Scenic Rivers System. “California”. Accessed January 29, 2025. https://www.rivers.gov/california
8 California Department of Conservation. “California Important Farmland Finder.” Accessed January 29, 2025. https://maps.conservation.ca.gov/DLRP/CIFF/
9 California Department of Conservation. “California Williamson Act Enrollment Finder”. Accessed January 29, 2025. https://maps.conservation.ca.gov/dlrp/WilliamsonAct/

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Five-Way Intersection Improvements 26 Final EIR/EA
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Resource Rationale for Dismissal
Community
Character and
Cohesion
The Project would construct improvements to an existing intersection. The improvements would not divide any existing community or neighborhood but would result in greater vehicle, bicycle, and pedestrian accessibility and safety at the intersection. Based on the Community Impact Memorandum10 (August 2024) , the Project would not adversely impact the health, safety, crime, delivery of public services, or quality of life for the local community. While the Project would acquire one full residential property and result in minor impacts to other residential and commercial properties, the Project would not result in a loss of parking, business relocations, loss of employment, or otherwise substantially impact the local economy. Minor impacts to commercial properties would include driveway conforms and realignment, which would result in minor changes in access and could potentially affect property values.

These changes are anticipated to have minor impacts and would not substantially impact the community’s character or cohesiveness.

Wetlands and Other
Waters
Based on the Natural Environment Study (Minimal Impacts) (NES[MI]) prepared for the Project (August 2024), no wetlands or other potentially jurisdictional aquatic features would be impacted as a result of the Project.

Plant Species
Based on the NES(MI)11 prepared for the Project, there are no special-status plant species within or adjacent to the Project area due to a lack of suitable habitat.

Invasive Species
Based on the NES(MI) prepared for the Project, there is limited potential to spread invasive plant species as the Project footprint is within a predominately disturbed and developed area. Therefore, the Project is not expected to result in an increase of invasive plant species within and/or adjacent to the Project boundaries. Additionally, in compliance with the Executive Order on Invasive Species (EO 13112), Caltrans does not use any of the species on the California list of invasive species for erosion control or landscaping.

10 The technical Community Impact Memorandum is incorporated into this Draft EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document. 11 The NES is incorporated into this Draft EIR/EA by reference. A copy of the NES is available for review at the locations listed inside the front cover of this document.

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Five-Way Intersection Improvements 27 Final EIR/EA
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HUMAN ENVIRONMENT

2.2 Existing and Future Land Use
The information in this section is based primarily on a Community Impact Memorandum (August 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

The Project is located within an urban area of the City of Napa. As shown in Figure 1.1- 3, the existing land uses within the Project limits consist of residential, commercial, light industrial, a school, a cemetery, and the Napa Valley Expo. Residential uses in the Project vicinity primarily consist of single-family residences. Commercial and light industrial uses in the vicinity consist of a car dealer, a marble and granite business, an auto shop, restaurant, and retail businesses.

Land use in Napa is guided by the City of Napa 2040 General Plan. The proposed 2040 land use plan for the Project vicinity is shown in Figure 2.2-1. As shown in Figure 2.2-1, the surrounding land uses at the Project intersection are largely anticipated to remain the same, with the exception of some commercial uses being converted to residential uses at the corners where East Avenue and Coombsville Road meet SR 121. Notable current land use projects within the Project vicinity are summarized in Table 2.2-1, below.

Table 2.2-1: Current Land Use Projects in the Project Vicinity Name and
Location
Description Distance to
Project Site
Status
Le Petit Elephant
Use Permit (15
Chapel Hill Drive)
A use permit authorizing a
daycare for up to 250
children, youth services,
and reduced parking.

0.3 miles Approved
Soscol Square
Shopping Center
(333 and 407
Soscol Avenue)
Redevelop the vacant site
with a new retail center
including a 55,000 square-
foot retail building, a 9,800
square-foot commercial
building, and a 4,970
square foot fast food
restaurant with a double
lane drive-through.

0.7 miles Approved
The Grange
Campground
(western side of SR
121, between
Stonecrest Drive
and Hagen Road)
Construct a campground
with up to five permanent
buildings, 100 fixed
recreational lodging units, a
recreational activity space,
and a pervious parking
area.

1.2 miles Pending

EXHIBIT A
Cabot Way
1st St
Lincoln Ave
Silvera
SilveradoTrl
Mont e c ito Blvd
Co ombsville Rd
PattonAve
Cayetano Dr
W Imola Ave
Ashlar Dr
5th St
Buttercup CtPine St
River Park Blvd
Muir St
Kansas Ave
Laredo St
Coombs St
st St
ce St
Shetler Ave
Shurtleff Ave
Seville Dr
T errace DrBirkdale Dr
Juarez St
East Ave
Soscol Ave
Elm St
Jefferson St
Yajo m e S t
Imperial Way
lay St
King Ave
Summit Ave
Highland Dr
Spring St
1st St
3rd St
Main St
3rd St
Coombs St
Napa St
Yo u n t S t
Brown St
Brown St
Randolph StFranklin St
Pearl St 1st St
Jackson St
Main St
Laurel St
Oak St
rd St
nd St
Central Ave
Pueblo Av
Soscol A
Napa R
iver
Napa
Valley
Sphere of Influence
Residential
Very Low Density Residential
Low Density Residential
Medium Density Residential
High Density Residential
T raditional Residential
Commercial
Napa Pipe Mixed Use
Mixed-Use
Residential Mixed Use
Corridor Mixed Use Low
Corridor Mixed Use High
Foster Road Mixed Use
Downtown Specific Plan
Industrial
Flex Industrial
Light Industrial
Business Park
Public-Serving
Public-Serving
Open Space & Parks
Map Base
City of Napa
Unincorporated Pockets
Rural Urban Limit
Downtown Specific Plan
do
cu
ru
C
3 2
e ve
A¾
College
Kennedy
Pk
South
Jefferson
Park
0 .25 .5 .75 1 Mile
Hospitality Commercial
General Commercial
Business Professional
Oxbow Commercial
Downtown Neighborhood
Downtown Mixed Use
Downtown Core Commercial
Downtown Public
Conservation
Greenbelt
Agriculture
Napa River
CITY OF NAPA 2040 GENERAL PLAN LAND USE DESIGNATIONS IN THE PROJECT AREA FIGURE 2.2-1

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The Project would require full ROW acquisition from one residential parcel at 801 Silverado Trail and major acquisition of the unimproved portions of the residential parcel at 36 Coombsville Road. Minor ROW acquisition from four commercial properties and two residential properties would be required to accommodate the roundabouts and/or shared use path to existing facilities. The Project’s required ROW acquisitions are summarized in Table 1.4-1 and shown in Figure 1.4-7.

The Project would require full acquisition of one residential property and, thus, would result in a change of land use for the parcel. The other major ROW acquisition would not change the residential use of 36 Coombsville Road. The minor acquisitions would result in a loss of land for commercial and residential properties; however, those minor acquisitions would not result in any changes to the use of these properties. Minor changes to the properties would include driveway conforms or realignments. The Project would not permanently remove any parking or substantially change access to these properties. Acquisition of one residential property for the use of constructing the proposed roundabouts would not result in a substantial change in land use patterns for the Project area.

The proposed Project would ease traffic congestion by introducing a traffic-calming circulation pattern, improving community connectivity in the Project area, and improving pedestrian and bicycle safety within and adjacent to the intersection. The Project would not substantially change existing or future land uses in the Project area that are identified in the General Plan.

2.2.1 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, or mitigation measures are required.

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2.3 Consistency with State, Regional, and Local Plans and Programs

2.3.1 Regional Transportation Plans
This Project is included in, and therefore consistent with, the 2025 FSTIP12 and the MTC RTP (Play Bay Area 2050).13
The No Build Alternative would not be consistent with the FSTIP and RTP.

2.3.2 City of Napa 2040 General Plan
The City of Napa 2040 General Plan contains a number of policies that are relevant to the proposed Project.

Policy TE 1-2: Foster a more connected system of streets, pedestrian facilities, and bicycle facilities as new development and redevelopment is undertaken, or as opportunities are presented.

Policy TE 2-6: Study and prepare designs for the following Study Corridors to evaluate future improvements for all modes in coordination with existing bicycle, pedestrian, and transportation plans. Coordinate with other agencies (e.g., NVTA, Caltrans, County of Napa, etc.) as needed for study development.
• Silverado Trail between Trancas Street and Soscol Avenue Policy TE 3-3: Promote a connected pedestrian and bicycle network that provides safe and direct access between destinations, such as from existing residential areas, schools and Napa Valley College, shopping, employment centers, and connections to regional trail systems, such as the Napa River Trail, the Vine Trail, and the Bay Trail.

Policy TE 3-4: Promote increased pedestrian and bicycle travel citywide. Opportunity areas include higher-intensity and mixed-use areas, including Downtown and the adjacent traditional neighborhoods, and the Jefferson Focus Area.

Policy TE 3-5: Improve connections to existing pedestrian and bicycle facilities from existing neighborhoods.

Policy TE 5-1: Improve the accessibility, safety, and traffic signal synchronization of intersections and access points along major corridors with an emphasis on creating Complete Streets while accommodating motor vehicle traffic flow consistent with prescribed levels of service.

Policy TE 5-4: Maintain acceptable traffic flow along the following crucial corridor arterials:
• Silverado Trail (SR121) – from Soscol Avenue to Trancas Street

12 TIP ID: NAP170009
13 RTP ID: 21-T07-056

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Policy TE 5-5: Maintain the automobile Level of Service (LOS) performance targets described herein as a local standards to determine where transportation improvements may be needed or required as part of the development approval process. Automobile LOS should not be below a mid-range LOS D, with the following exceptions. A mid- range LOS E is permitted in the Downtown area bounded by Soscol Avenue, First Street, California Boulevard, and Third Street; on Jefferson Street between Third Street and Old Sonoma Road; and on Silverado Trail between Soscol Avenue and First Street.

LOS E is also permitted for signalized intersections on State Highway facilities within Napa.

The Build Alternative would be consistent with the policies listed above by reducing traffic congestion and delay and improving bicycle and pedestrian safety, accessibility, and connectivity. The No Build Alternative would not be consistent with these policies as it would not make any improvements to the existing intersection, which is part of the Silverado Trail corridor identified in Policies TE 2-6 and TE 5-4.

2.3.3 City of Napa Bicycle Plan
The City of Napa Bicycle Plan was developed as a component of the Countywide Bicycle Plan and was adopted by the Napa City Council on May 4, 2021. The City of Napa Bicycle Plan is intended to guide development of infrastructure, programs, and policies that improve the bicycling environment for all residents and visitors in the Napa Valley community.

The proposed Project would improve bicycle safety and connectivity through the Project intersection by constructing a new shared-use path. The No Build Alternative would not make any bicycle facility improvements to the Project intersection.

2.3.4 City of Napa Pedestrian Plan
The City of Napa Pedestrian Plan was developed as a component of the Countywide Pedestrian Plan and was adopted by the Napa City Council on February 21, 2017. The City of Napa Pedestrian Plan is intended to provide a framework for expanding policies in the General Plan, ADA Transition Plan, public works standards, and Municipal Code as well as future investments to create a safe and continuous pedestrian network Citywide.

The proposed Project would improve pedestrian safety and connectivity through the Project intersection by constructing a new shared-use path, sidewalks, marked crossings, and pedestrian refuges. The No Build Alternative would not make any pedestrian facility improvements to the Project intersection.

2.3.5 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, or mitigation measures are required.

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2.4 Growth

2.4.1 Regulatory Setting
The Council on Environmental Quality (CEQ) regulations, which established the steps necessary to comply with NEPA, require evaluation of the potential environmental effects of all proposed federal activities and programs. This provision includes a requirement to examine indirect effects, which may occur in areas beyond the immediate influence of a proposed action and at some time in the future. The CEQ regulations (40 Code of Federal Regulations [CFR] 1508.8) refer to these consequences as indirect impacts. Indirect impacts may include changes in land use, economic vitality, and population density, which are all elements of growth.

CEQA also requires the analysis of a project’s potential to induce growth. The CEQA Guidelines (Section 15126.2[d]) require that environmental documents “…discuss the ways in which the proposed project could foster economic or population growth, or the construction of additional housing, either directly or indirectly, in the surrounding environment…”

2.4.2 Environmental Consequences
The information in this section is based primarily on a technical Community Impact Memorandum (August 2024) prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

The Project is limited to improvements to an existing intersection and would not change land use patterns or density. The Project is located within, and is intended to serve, an urbanized and mostly-developed area of Napa. The Project would not open additional areas to development.

The Project is intended to reduce traffic congestion and vehicle delay and improve safety conditions. Existing traffic conditions are the result of growth that has already occurred in the area in accordance with land uses identified in the City’s adopted General Plan. One result of reducing congestion and improving safety can be to increase accessibility, which can in turn affect the timing and location of growth elsewhere. However, due to the urban location of this intersection, the Project is not expected to drive growth in unplanned areas or areas where growth is not currently foreseeable, therefore, the Project would not result in an unplanned population increase.

The Project purpose is limited to serving the local urbanized area. To the extent that a reduction in congestion makes the area more attractive for development, the Project could facilitate growth in the area. The General Plan contains policies that ensure that the future capacity of services (e.g., schools, utilities, police and fire protection, libraries, parks, etc.) would be adequate to serve that planned growth. Therefore, any growth indirectly facilitated by the Project would not substantially affect resources of concern.

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Five-Way Intersection Improvements 33 Final EIR/EA
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No Build Alternative
The No Build Alternative would potentially limit planned growth as congestion worsens at SR 121, Third Street, Coombsville Road, and East Avenue.

2.4.3 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, and/or mitigation measures are necessary because the Project would not induce growth beyond what is expected to occur in the area.

EXHIBIT A

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2.5 Relocations and Real Property Acquisition

2.5.1 Regulatory Setting
Caltrans’ Relocation Assistance Program (RAP) is based on the Federal Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970, as amended (Uniform Act), and Title 49 Code of Federal Regulations (CFR) Part 24. The purpose of the RAP is to ensure that persons displaced as a result of a transportation project are treated fairly, consistently, and equitably so that such persons will not suffer disproportionate injuries as a result of projects designed for the benefit of the public as a whole. Please see Appendix C for a summary of the RAP.

All relocation services and benefits are administered without regard to race, color, national origin, persons with disabilities, religion, age, or sex. Please see Appendix B for a copy of the Caltrans’ Title VI Policy Statement.

2.5.2 Affected Environment
The Project is located within an urban area of the City of Napa. As shown in Figure 1.1- 3:, the existing land uses within the Project limits consist of residential, commercial, light industrial, and public-serving facilities including a school, cemetery, and the Napa Valley Expo. Residential uses in the Project vicinity primarily consist of single-family residences. Commercial and light industrial uses in the vicinity consist of a car dealer, a marble and granite business, an auto shop, and retail businesses.

2.5.3 Environmental Consequences
The majority of the proposed improvements would be constructed within the existing Caltrans and City of Napa rights-of-way for SR 121 and local streets, respectively.

There are locations, however, where the proposed roundabouts would require additional right-of-way that would directly impact businesses and one residence. Based on preliminary design, which is subject to revision during final design, the Project would require full acquisition of one residential parcel at 801 Silverado Trail and major acquisition of the unimproved portions of the residential parcel at 36 Coombsville Road.

Minor right-of-way acquisition from five commercial properties and two residential properties would also be required to accommodate the roundabouts and/or shared use path to existing facilities (see Table 1.4-1).

No Build Alternative
No relocation or real property acquisition impacts would occur under the No Build Alternative.

2.5.4 Avoidance, Minimization, and/or Mitigation Measures The following measure is included in the Project for the purpose of avoiding, minimizing, and mitigating the relocation impacts of the Project.

EXHIBIT A

Five-Way Intersection Improvements 35 Final EIR/EA
Napa, California July 2026
MM-RRP-1: The Project would comply with all requirements of the Uniform Relocation Act to ensure residents displaced by the Project would be properly compensated and relocated, as necessary.

EXHIBIT A

Five-Way Intersection Improvements 36 Final EIR/EA
Napa, California July 2026

2.6 Utilities/Emergency Services

2.6.1 Affected Environment
Various utility lines (e.g., gas, electric, water, communications, sanitary sewer, stormwater, etc.) cross the existing intersection and are located along/within the local streets in the vicinity of the Project.

Fire protection services for the project area are provided by the City of Napa Fire Department (NFD). The closest fire stations to the Project are Station No. 1, located at 930 Seminary Street and Station No. 4, located at 251 Gasser Drive, approximately one mile west and one mile south of the Project, respectively. Police protection services for the project area are provided by the City of Napa Police Department (NPD), which is headquartered at 1539 First Street, approximately one mile west of the Project.

2.6.2 Environmental Consequences
Increased Demand for Utilities and Services
The Project is limited to improving the existing intersection and is intended to improve traffic operations in the Project area. As stated previously in Section 2.4 Growth, the Project would not induce unplanned growth but may indirectly facilitate the planned growth of the area as identified in the General Plan. The General Plan contains policies that ensure the future capacity of utilities and emergency services would be adequate to serve that planned growth.

Utility Relocation Impacts
Due to the significant grading that will be required to construct the proposed roundabouts, the water line that runs from Third Street will need to be relocated and six joint utility poles may need to be relocated or undergrounded. In addition, adjustment of utility vaults to match the final pavement surface elevation would be required along SR 121. All other existing utilities would be protected in place. Utility relocations and adjustments would occur within the existing City right-of-way. The proposed utility relocations and adjustments would be relatively minor and would be subject to the construction-related mitigation measures and standard conditions described throughout this Final EIR/EA (see Section 2.9 Cultural Resources, Section 2.11 Water Quality and Stormwater Runoff, Section 2.14 Hazardous Waste/Materials, Section 2.15 Air Quality, Section 2.16 Noise, Section 2.18 Natural Communities, Section 2.19 Animal Species, and Section 2.20 Threatened and Endangered Species). No disruption of any utility services for an extended period of time (i.e., more than 24 hours) is expected to be necessary.

Impacts on Emergency Vehicle Response Times
The Project would not cut off or adversely impact the existing emergency response routes along SR 121, Third Street, Coombsville Road, or East Avenue. At least one travel lane in each direction on each roadway will be kept open during peak hours.

Closures, if necessary, will occur only at night. A TMP would also be prepared in

EXHIBIT A

Five-Way Intersection Improvements 37 Final EIR/EA
Napa, California July 2026
coordination with the NFD and NPD to ensure that adequate emergency access is provided throughout project construction. Project operation would improve traffic circulation and safety at the site intersection, resulting in a long-term benefit to emergency response times.

No Build Alternative
The No Build Alternative would not relocate any existing utility infrastructure, result in any increased utility demand, or affect emergency response times. The No Build Alternative would also not result in any long- term benefit to emergency response times and would negatively affect response times as traffic conditions at the Project intersection worsen over time.

2.6.3 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, or mitigation measures are required.

EXHIBIT A

Five-Way Intersection Improvements 38 Final EIR/EA
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2.7 Traffic and Transportation/Pedestrian and Bicycle Facilities

2.7.1 Regulatory Setting
Caltrans, as assigned by the Federal Highway Administration (FHWA), directs that full consideration should be given to the safe accommodation of pedestrians and bicyclists during the development of Federal-aid highway projects (see 23 Code of Federal Regulations [CFR] 652). It further directs that the special needs of the elderly and the disabled must be considered in all Federal-aid projects that include pedestrian facilities.

When current or anticipated pedestrian and/or bicycle traffic presents a potential conflict with motor vehicle traffic, every effort must be made to minimize the detrimental effects on all highway users who share the facility.

In July 1999, the U.S. Department of Transportation (USDOT) issued an Accessibility Policy Statement pledging a fully accessible multimodal transportation system.

Accessibility in federally assisted programs is governed by the USDOT regulations (49 CFR 27) implementing Section 504 of the Rehabilitation Act (29 United States Code [USC] 794). The FHWA has enacted regulations for the implementation of the 1990 Americans with Disabilities Act (ADA), including a commitment to build transportation facilities that provide equal access for all persons. These regulations require application of the ADA requirements to Federal-aid projects, including Transportation Enhancement Activities.

2.7.2 Affected Environment
The information in this section is based primarily on a Traffic Operations Analysis Report (July 2024) prepared for the Project, which is incorporated into this Final EIR/EA by reference. This report is available for review at the locations listed inside the front cover of this document.

2.7.2.1 Roadways
Roadways that provide primary access to the project intersection are SR 121, Third Street, Coombsville Road, and East Avenue. The traffic study area also includes Hennessey Drive. Each of these roadways are described below:
• SR 121, in the Project vicinity, is a two-lane, north-south highway and is classified by the City as a Principal Arterial. The highway serves residential and commercial land uses within the City and carries regional traffic through Napa County.
• Third Street is a two-lane, east-west, Minor Arterial that serves residential and commercial land uses. Third Street runs west from the Project intersection, crosses the Napa River, and connects to Downtown Napa.
• Coombsville Road is a two-lane, east-west, Minor Arterial that serves residential and commercial land uses. It connects from the Project intersection to rural unincorporated areas to the east.

EXHIBIT A

Five-Way Intersection Improvements 39 Final EIR/EA
Napa, California July 2026
• East Avenue is a two-lane, north-south, Major Collector that serves residential land uses. It parallels SR 121 and connects to the Project intersection. • Hennessey Drive is a two-lane, east-west, Local Street that serves residential land uses. It connects from SR 121 to Coombsville Road, south of the Project intersection.

2.7.2.2 Bicycle and Pedestrian Facilities
Class II bicycle facilities exist within the Project vicinity along Third Street, west of SR 121 and along Coombsville Road, southeast of SR 121. Class III bicycle facilities14 exist along East Avenue, east of SR 121. Existing bicycle facilities are shown in Figure 2.7-1.

At the Project intersection, there are crosswalks with basic striping on all five legs with curb ramps. There is no marked crosswalk or curb ramp of the channelized right turn from northbound SR 121 to Coombsville Road. Continuous sidewalks exist on the northeast side of SR 121, the south side of East Avenue, the north side of Coombsville Road, and the south side of Third Street. There are existing discontinuous sidewalks on the northwest and southwest sides of SR 121 that extend for approximately 50 feet and 200 feet, respectively. No other sidewalks exist at the Project intersection.

2.7.2.3 Transit Service
Transit service in the Project vicinity is provided in both directions along Third Street and East Avenue via Vine Transit Route E operated by NVTA. Route E is a local bus loop connecting the Soscol Gateway Transit Center with Vintage High School. Within the Project vicinity, stops exist on Third Street east of Juarez Street in both directions and on East Avenue, east of SR 121 in the eastbound direction. Route E operates on weekdays with 30- to 60-minute headways and on Saturdays with 60-minute headways.

Existing transit service locations are shown in Figure 2.7-2.

2.7.2.4 Existing Traffic Volumes
Peak period intersection turning movement counts and daily roadway segment counts were collected in November 2023 for the AM peak period (6:00 AM to 9:00 AM) and the PM peak period (2:00 PM to 6:30 PM). Typically, Friday counts are not considered representative of typical traffic conditions and are managed separately, if appropriate.

However, at the study intersections it was observed that the Friday PM peak hour data and average daily traffic (ADT) is consistently higher when compared to the other weekday PM time periods. As such, the Friday data is included in the analysis in lieu of traditional weekday PM analysis. Table 2.7-1 provides a summary of the counts and a comparison across various days and time periods.

14 Class III Bike Lanes (Bike Routes and Bicycle Boulevards) are designated with pavement markings or signage to indicate a shared lane environment between bicyclists and drivers.

EXHIBIT A
Source: GHD, February 7, 2024.

Silverado Trl
RaymondAve
Dewoody St
Fairview Dr
Capitol
aDr
EvansA v e
Juarez S
t
Elan W
ay
Aguirre Way
Montecito Bl
2nd St
Plaz
aAve
Capitola Ct
HennesseyD r
Post St
Ramona Ave
e v A s i v a D
Taylor St
3rd St
East Ave
CoombsvilleR d
Julian Ave
e v A n a m f f o H
Bonita Ave
e v A l l e n n i L
121
1 2
3 Legend
Study Intersections
Regional Bike Facilities
Class I
Class II
Class III
Roads
Highways
0 10050 200 300 400 Feet
vd
EXISTING BICYCLE FACILITIES FIGURE 2.7-1

EXHIBIT A
Source: GHD, February 7, 2024.

Silverado T
rl
RaymondAve
Dewoody St
Fairview Dr
Capitol
aDr
EvansA v e
Juarez S
t
Elan W
ay
Aguirre Way
Montecito Blvd
2nd St
Plaz
aAve
Capitola Ct
Hennessey Dr
Post St
Ramona Ave
e v A s i v a D
Taylor St
3rd St
East Ave
Coombsville Rd
Julian Ave
e v A n a m f f o H
Bonita Ave
e v A l l e n n i L
121
1 2
3 Legend
Study Intersections
Bus routes
E
Bus stops
Highways
Roads
0 10050 200 300 400 Feet
EXISTING TRANSIT FACILITIES FIGURE 2.7-2

EXHIBIT A

Five-Way Intersection Improvements 42 Final EIR/EA
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Table 2.7-1: Traffic Volumes Comparison
Scenario Location Tue
11/14/23
Wed
11/15/23
Thu
11/16/23
Fri
11/17/23
Sat
11/18/23
Sun
11/19/23
AM Peak
Hour
Intersection
Volume 1,634 1,641 1,640 1,584 -- --
PM Peak
Hour
Intersection
Volume 1,648 1,650 1,688 1,754 -- --
AM Peak
Hour
SR 121 S/O
3rd St 836 867 896 867 841 780
PM Peak
Hour
SR 121 S/O
3rd St 947 898 943 1,032 818 863
ADT SR 121 S/O
3rd St 10,673 11,057 11,632 12,016 9,492 9,356
ADT Coombsville
Rd E/O SR
121
6,530 6,463 6,708 6,919 4,627 4,016

Caltrans publishes ADT data in a count book annually for all the facilities on the State Highway System. As noted in the count book, few locations are counted continuously, and the resulting counts are adjusted to derive an estimate of ADT. Data for 2021 was reviewed from the Caltrans count book in the Project vicinity. The 2021 ADT data on Route 121 south of Third Street was 13,600. Table 2.7-2 presents the counted 2023 roadway volumes for Wednesday and Friday.

Table 2.7-2: Roadway Segment Volume Summary
Roadway Segment Wednesday Friday
SR 121 South of Third
Street 11,057 12,016
Coombsville Road Southeast of Third
Street 6,463 6,919

2.7.2.5 Existing Traffic Operations
Operating conditions at the study intersections were measured using the “level of service” (LOS) concept as the metric for NEPA, whereby traffic demand is evaluated in the context of capacity. The methodology computes a level of service taking into account factors such as the demand for each traffic movement (i.e., left turns, straight, right turns), the number of lanes, and (where applicable) signal timing. Based on these factors, the methodology computes the average delay per vehicle at the intersection to which a corresponding LOS is assigned. As summarized in Table 2.7-3, level of service can range from “LOS A”, representing free-flow conditions, to “LOS F”, representing jammed/over-saturated conditions.

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Five-Way Intersection Improvements 43 Final EIR/EA
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The intersection LOS results for the existing weekday AM and Friday PM peak hours are presented in Table 2.7-4. The City of Napa 2040 General Plan Policy TE 5-5 identifies a target of LOS E for the Project intersection, LOS mid E for the SR 121 and Hennessey Drive intersection, and LOS mid-D for the Coombsville Road and Hennessey Drive intersection.

Table 2.7-3: Level of Service Definitions for Signalized Intersections Level of Service Description of Operations
Average Control
Delay
(seconds/vehicle)
A
Insignificant Delays: No approach phase is
fully utilized and no vehicle waits longer
than one red indication.
≤ 10
B
Minimal Delays: An occasional approach
phase is fully utilized. Drivers begin to feel
restricted.
> 10 to 20
C
Acceptable Delays: Major approach phase
may become fully utilized. Most drivers feel
somewhat restricted.
> 20 to 35
D
Tolerable Delays: Drivers may wait through
no more than one red indication. Queues
may develop but dissipate rapidly, without
excessive delays.
> 35 to 55
E
Significant Delays: Volumes approaching
capacity. Vehicles may wait through several
signal cycles and long vehicle queues from
upstream.
> 55 to 80
F
Excessive Delays: Represents conditions at
capacity, with extremely long delays.

Queues may block upstream intersections.
> 80
Notes: Average Control Delay includes the time for initial deceleration delay, queue move-up time, stopped delay, and final acceleration.

Table 2.7-4: Existing Intersection Levels of Service
Intersection Control
Type1, 2
Weekday
AM Peak
Hour
Delay
(sec)
Weekday
AM Peak
Hour
LOS
Friday
PM Peak
Hour
Delay
(sec)
Friday
PM Peak
Hour
LOS
SR 121/Coombsville Road/
Third Street/East Avenue
Signal

71.6 E 57.1 E
EB Left/Thru 93.5 F 61.3 E
EB Bear Right/Right 49.5 D 43.6 D
WB Hard Left/Left/
Thru/Right 62.2 E 42.4 D
NB Left 53.0 D 82.2 F

EXHIBIT A

Five-Way Intersection Improvements 44 Final EIR/EA
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Intersection Control
Type1, 2
Weekday
AM Peak
Hour
Delay
(sec)
Weekday
AM Peak
Hour
LOS
Friday
PM Peak
Hour
Delay
(sec)
Friday
PM Peak
Hour
LOS
NB Thru/Right/ Hard
Right 71.5 E 48.6 D
SB Left/Bear Left 98.4 F 76.1 E
SB Thru/Right 32.5 C 31.9 C
NW Hard Left/Bear Left/
Bear Right/Hard Right 118.5 F 116.7 F
SR 121/Hennessey Drive
TWSC

18.7 C 26.0 D
EB Left/Thru/Right 0.0 A 0.0 A
WB Left/Thru/Right 18.7 C 26.0 D
NB Left/Thru/Right 0.0 A 0.0 A
SB Left/Thru/Right 8.4 A 8.4 A
Coombsville Road/
Hennessey Drive
TWSC

12.6 B 12.7 B
EB Left/Right 12.6 B 12.7 B
NB Left/Thru 8.8 A 8.6 A
SB Thru/Right 0.0 A 0.0 A
Notes:
1TWSC = Two Way Stop Control
2LOS = Delay based on worst movement for TWSC intersections, average of all approaches for Signal. 3Bold = Unacceptable LOS conditions

2.7.2.6 Existing Collision Rates
Data was obtained and analyzed from both the Caltrans Traffic Accident Surveillance and Analysis System (TASAS) and the City of Napa Police Department for the latest 5- year period in the project area along SR 121. Table 2.7-5 presents the collision rates for the Project intersection compared to the average rate for similar facilities across the State of California, reported in the rate per million vehicle miles. As shown, there were 10 collisions reported within proximity of the Project intersection during the five-year study period. While there were no fatal collisions reported over the five-year study period, the rate of total collisions at the Project intersection was higher than the average for other similar facilities across the State.

Table 2.7-5: Collision Rates (per million vehicle miles) Location Total # of
Crashes Fatal Crashes Fatal & Injury
Crashes Total
SR 121 PM 7.1
to 7.5 10 0.00 0.421 1.405
Average Rates -- 0.009 0.30 0.61

EXHIBIT A

Five-Way Intersection Improvements 45 Final EIR/EA
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2.7.3 Environmental Consequences
Future Traffic Conditions
Intersection traffic forecasts were developed in coordination with the City and Napa Valley Transportation Authority (NVTA) for Year 2026 (Opening Year), Year 2036 (Interim Year), and Year 2046 (Design Year). The LOS results for the future No Build conditions are summarized in Table 2.7-6.

The proposed roundabouts would allow for calmer speeds through the intersection, continuous flow of movements during lower-demand periods, better visibility of pedestrians and bicyclists, fewer conflict points, and potential U-turn movements. The LOS results for the future Build conditions are summarized in Table 2.7-7.

As shown in Table 2.7-7, all movements would perform at LOS B or better under the Build Alternative and result in less delay as compared to the No Build Alternative.

Queues are expected to stay within the available storage capacity of the proposed roundabouts and thus, would not impact operations at the SR 121/Hennessey Drive or Coombsville Road/Hennessey Drive intersections. The Build Alternative would positively affect existing traffic conditions, while conditions would worsen under the No Build Alternative.

EXHIBIT A

Five-Way Intersection Improvements 46 Final EIR/EA
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Table 2.7-6: Future No Build LOS Conditions
Intersection
2026
Week
day
AM
Delay
2026
Week
day
AM
LOS
2026
Friday
PM
Delay
2026
Friday
PM
LOS
2036
Week
day
AM
Delay
2036
Week
day
AM
LOS
2036
Friday
PM
Delay
2036
Friday
PM
LOS
2046
Week
day
AM
Delay
2046
Week
day
AM
LOS
2046
Friday
PM
Delay
2046
Friday
PM
LOS
SR 121/Coombsville
Rd/Third St/East Ave 80.4 F 81.8 F 109.1 F 94.2 F 143.7 F 126.0 F EB Left/Thru 108.8 F 73.0 E 180.0 F 87.2 F 202.2 F 146.3 F EB Bear Right/Right 56.9 E 55.0 D 108.5 F 68.5 E 199.8 F 158.8 F WB Hard Left
/Left/Thru/Right 75.6 E 49.4 D 113.5 F 66.1 E 155.7 F 75.0 E NB Left 59.4 E 67.1 E 81.1 F 128.9 F 91.8 F 87.6 F
NB Thru/Right/Hard
Right 64.2 E 53.8 D 67.6 E 57.8 E 77.5 E 65.2 E
SB Left/Bear Left 117.1 F 94.6 F 140.5 F 92.7 F 165.0 F 105.6 F SB Thru/Right 33.3 C 35.7 D 33.7 C 36.1 D 35.2 D 41.0 D NW Hard Left/ Bear
Left/Bear Right/
Hard Right
152.6 F 241.0 F 220.6 F 284.3 F 302.8 F 385.9 F
SR 121/Hennessey Dr 20.3 C 33.4 D 30.1 D 75.4 F 52.4 F 202.7 F EB Left/Thru/Right 0.0 A 0.0 A 0.0 A 0.0 A 0.0 A 0.0 A
WB Left/Thru/ Right 20.3 C 33.4 D 30.1 D 75.4 F 52.4 F 202.7 F NB Left/Thru/Right 0.0 A 0.0 A 0.0 A 0.0 A 0.0 A 0.0 A
SB Left/Thru/Right 8.5 A 8.5 A 8.8 A 8.9 A 9.2 A 9.3 A
Coombsville Rd/
Hennessey Dr 13.7 B 14.1 B 14.8 B 15.2 C 15.9 C 16.9 C
EB Left/Right 13.7 B 14.1 B 14.8 B 15.2 C 15.9 C 16.9 C NB Left/Thru 9.0 A 8.7 A 9.2 A 8.9 A 9.5 A 9.2 A
SB Thru/Right 0.0 A 0.0 A 0.0 A 0.0 A 0.0 A 0.0 A

EXHIBIT A

Five-Way Intersection Improvements 47 Final EIR/EA
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Table 2.7-7: Future Build LOS Conditions
Intersection
2026
Week
day
AM
Delay
2026
Week
day
AM
LOS
2026
Friday
PM
Delay
2026
Friday
PM
LOS
2036
Week
day
AM
Delay
2036
Week
day
AM
LOS
2036
Friday
PM
Delay
2036
Friday
PM
LOS
2046
Week
day
AM
Delay
2046
Week
day
AM
LOS
2046
Friday
PM
Delay
2046
Friday
PM
LOS
SR 121/Third St/
East Ave w/ Project 9.1 A 10.2 B 9.7 A 11.1 B 11.1 B 12.7 B NB Left/Thru 7.6 A 7.1 A 7.9 A 7.4 A 8.3 A 7.9 A
NB Right 3.4 A 2.9 A 3.3 A 2.9 A 3.4 A 2.9 A
WB Left/Thru/Right 10.8 B 8.5 A 11.9 B 9.0 A 13.5 B 10.0 A SB Left/Thru/Right 10.7 B 13.4 B 11.4 B 14.4 B 13.2 B 16.6 B EB Left/Thru/Right 11.3 B 13.9 B 12.1 B 16.1 B 15.1 B 19.7 B SR 121/Coombsville
Rd w/ Project 8.0 A 7.4 A 8.5 A 7.6 A 9.5 A 8.5 A
NB Thru/Right 12.2 B 10.8 B 13.0 B 11.1 B 15.2 B 12.9 B WB Left/Right 10.3 B 9.4 A 11.0 B 9.8 A 12.9 B 11.3 B
SB Left 4.5 A 4.6 A 4.7 A 4.7 A 4.9 A 4.8 A
SB Thru 3.9 A 4.8 A 4.0 A 5.0 A 4.2 A 5.1 A

EXHIBIT A

Five-Way Intersection Improvements 48 Final EIR/EA
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Impacts to Transit Facilities
The Build Alternative would not make any direct improvements to transit facilities but would benefit transit service in the vicinity by reducing vehicle congestion and delay at the Project intersection. Traffic delay at the Project intersection would worsen under the No Build Alternative, which would negatively affect transit service in the vicinity.

Impacts to Bicycle and Pedestrian Facilities
The Build Alternative would result in improved bicycle and pedestrian connectivity, accessibility, and safety by providing a new shared-used path and sidewalks through the proposed roundabouts. The No Build Alternative would not make any bicycle or pedestrian improvements.

Short-Term Transportation Impacts During Construction
Project construction is anticipated to last approximately 18 months. During construction, at least one travel lane in each direction of SR 121 will be kept open during peak hours, as will Third Street, Coombsville Road, and East Avenue. Closures, if necessary, will occur only at night. Construction activities may potentially include detours. Detour routes may include the use of local streets such as Hennessey Drive, Soscol Avenue, First Street, Juarez Street, and Taylor Street. Potential detour roadways are shown in Figure 2.7-3. Advance notification of construction work will be provided to the community. Prenotification will be provided at Soscol Avenue and First Street encouraging drivers to take alternate routes, which may lower traffic volumes in the project area during construction. Cyclists will be required to share the road with vehicles during some construction stages and signing and striping will be provided to warn drivers. Pedestrian detours will be accommodated for locations where existing facilities occur.

Prior to construction, as is standard practice on all large infrastructure improvement projects, a TMP will be prepared. The TMP will address all traffic-related aspects of construction including, but not limited to, the following: traffic handling in each stage of construction, pedestrian safety/access, and bicycle safety/access. A component of the TMP will involve public dissemination of construction-related information through notices to the neighborhoods, press releases, and the use of changeable message signs. The TMP will also include advance coordination with the NFD, as well as with other emergency responders (e.g., police, ambulance, etc.), especially with regard to any temporary lane closures or detours.

2.7.4 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, or mitigation measures are required.

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2.8 Visual/Aesthetics

2.8.1 Regulatory Setting
The National Environmental Policy Act (NEPA) of 1969, as amended, establishes that the federal government use all practicable means to ensure all Americans safe, healthful, productive, and aesthetically (emphasis added) and culturally pleasing surroundings (42 United States Code [USC] 4331[b][2]). To further emphasize this point, the Federal Highway administration (FHWA), in its implementation of NEPA (23 USC 109[h]), directs that final decisions on projects are to be made in the best overall public interest taking into account adverse environmental impacts, including among others, the destruction or disruption of aesthetic values.

The California Environmental Quality Act (CEQA) establishes that it is the policy of the state to take all action necessary to provide the people of the state “with…enjoyment of aesthetic, natural, scenic and historic environmental qualities” (CA Public Resources Code [PRC] Section 21001[b]).

California Streets and Highways Code Section 92.3 directs Caltrans to use drought resistant landscaping and recycled water when feasible and incorporate native wildflowers and native and climate-appropriate vegetation into the planting design when appropriate.

2.8.2 Affected Environment
The information in this section is based primarily on a Visual Impact Assessment Memorandum (September 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

Existing Visual Character
The existing visual character of the Project area is that of a suburban neighborhood.

The immediate Project site is characterized by the existing intersection and residential and commercial developments. The surrounding buildings are generally low in height, diverse in character, and spaced apart with varying setbacks and landscaping in between. Mature trees and less developed land uses such as the Napa Valley Expo and Tulocay Cemetery break up the built environment. Existing sources of light include overhead lights at the intersection and crosswalks, streetlights down Third Street, overhead parking lot lights, and residential light sources.

Existing Visual Quality
Visual quality in the Project area is of low to medium quality. The surrounding suburban development detracts from the visual environment but is softened by some vegetation and mature trees. There is no consistent aesthetic or uniform design in terms of architectural style, pedestrian circulation, setbacks from the road and corners, and landscaping. This lack of unity renders the Project area from having memorable scenic qualities.

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Viewers
Viewer groups for the proposed Project include highway neighbors and highway users.

Highway neighbors (people who have views to the road) includes residents, workers, pedestrians, bicyclists, and motorized transportation users. They will likely have moderate to high levels of sensitivity and exposure to changes in aesthetics depending on the frequency and mode of travel on adjacent streets, and whether they live or work in the immediate community. Napa County residents are highly sensitive to changes to their environment, including vegetation removal.

Highway users (people who have views from the road) may include people noted above as well as tourists and commuters. Their exposure and sensitivity differ depending on their reason for travel. Tourists and recreational travelers are more attuned to their surroundings and have higher expectations of scenic value but have less exposure due to more infrequent travel. Commuters are more focused on their destinations and therefore less sensitive to their environment, however, they tend to have greater exposure as part of their regular routines. Overall, highway neighbors and users are expected to have a moderate to moderate-high viewer response.

Viewpoints
SR 121 within the Project limits is listed as an eligible, but not officially designated, state scenic highway. Scenic resources visible from the Project limits include a large stand of natural-occurring vegetation including oak trees between northbound SR 121 and Coombsville Road and the residence at 801 Silverado Trail which is listed in the City of Napa Historic Resources Inventory as a contributor to the East Napa Historic District.

Due to the existing development and topography of the site, there are no open landscape views, water views, rock outcroppings, or heritage trees visible from the Project limits. There are some foothill mountains visible in the distance, but views are obstructed by existing landcover and landform.

2.8.3 Environmental Consequences
The Project’s primary impact to visual resources is the removal of existing trees and the residence at 801 Silverado Trail. In addition, there will be an increase in paved area to accommodate the proposed roundabouts as well as the introduction of retaining walls of various heights where there were once none. New overhead lights would also be added which would increase the nighttime light levels in the neighborhoods immediately adjacent to the Project. New landscaping and aesthetic treatments would soften the environment and provide context sensitivity and increased unity. Overall, the Project is expected to result in a moderate permanent visual change and moderate to moderate- high viewer response.

Temporary visual impacts would occur during construction resulting from the various equipment and materials required for the work and the addition of light and glare during nighttime work. Such impacts would be for a limited period of time during the construction phase of the Project.

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No-Build Alternative
The No Build Alternative would not result in any temporary or permanent changes to the existing visual character or quality.

2.8.4 Avoidance, Minimization, and/or Mitigation Measures The following measures are included in the Project for the purpose of avoiding and minimizing the visual effects of the Project.

AMM VIS-1.1: The Project shall survey exact locations of existing trees and include the tree locations in the plan set during the design phase. Where the pruning of trees is required to accommodate construction operations, pruning shall be done under the supervision of a certified arborist.

AMM VIS-1.2: Where feasible, the roundabout island, medians, and parkway strips shall be landscaped with a combination of trees and ornamental planting. Decorative paving shall be incorporated for areas too narrow to plant or where planting is not easily maintained.

AMM VIS-1.3: Retaining walls, barriers, paving, and roundabouts shall incorporate aesthetic treatments that use context-sensitive design, textures, and/or colors to help minimize glare and support visual unity at the Project site.

AMM VIS-1.4: During construction operations, unsightly material and equipment in staging areas shall be placed where they are less visible and/or covered where possible. Construction activities shall limit all construction lighting to within the area of work and avoid light trespass in residential areas through directional lighting, shielding, and other measures as needed.

AMM VIS-1.5: Light added as permanent features shall be shielded to the extent feasible and light trespass shall be minimized.

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2.9 Cultural Resources

2.9.1 Regulatory Setting
The term “cultural resources,” as used in this document, refers to the “built environment” (e.g., structures, bridges, railroads, water conveyance systems, etc.), places of traditional or cultural importance, and archaeological sites (both prehistoric and historic), regardless of significance. Under federal and state laws, cultural resources that meet certain criteria of significance are referred to by various terms including “historic properties,” “historic sites,” “historical resources,” and “tribal cultural resources.” Laws and regulations dealing with cultural resources include:

The National Historic Preservation Act (NHPA) of 1966, as amended, sets forth national policy and procedures for historic properties, defined as districts, sites, buildings, structures, and objects included in or eligible for listing in the National Register of Historic Places (NRHP). Section 106 of the NHPA requires federal agencies to take into account the effects of their undertakings on historic properties and to allow the Advisory Council on Historic Preservation (ACHP) the opportunity to comment on those undertakings, following regulations issued by the ACHP (36 Code of Federal Regulations [CFR] 800). On December 6, 2024, the Second Amended Section 106 Programmatic Agreement (PA) among the Federal Highway Administration (FHWA), the ACHP, the California State Historic Preservation Officer (SHPO), the United States Army Corps of Engineers’ Sacramento District, San Francisco District, and Los Angeles District and Caltrans went into effect for Caltrans projects, both state and local, with FHWA involvement. The PA implements the ACHP’s regulations, 36 CFR 800, streamlining the Section 106 process and delegating certain responsibilities to Caltrans.

The FHWA’s responsibilities under the PA have been assigned to Caltrans as part of the Surface Transportation Project Delivery Program (23 United States Code [USC] 327).

The criteria for listing in the NRHP are as follows:
• Criteria A: Is associated with events that have made a significant contribution to the broad patterns of our history.
• Criteria B: Is associated with the lives of persons significant in our past. • Criteria C: Embodies the distinctive characteristics of a type, period or method of construction, or represents the work of a master, or possesses high artistic values, or represents a significant and distinguishable entity whose components may lack individual distinction.
• Criteria D: Has yielded, or may be likely to yield, information important in history or prehistory.

CEQA requires the consideration of cultural resources that are historical resources and tribal cultural resources, as well as “unique” archaeological resources. California Public Resources Code (PRC) Section 5024.1 established the California Register of Historical

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Resources (CRHR) and outlined the necessary criteria for a cultural resource to be considered eligible for listing in the CRHR and, therefore, a historical resource.

Historical resources are defined in PRC Section 5020.1(j). In 2014, Assembly Bill 52 (AB 52) added the term “tribal cultural resources” to CEQA, and AB 52 is commonly referenced instead of CEQA when discussing the process to identify tribal cultural resources (as well as identifying measures to avoid, preserve, or mitigate effects to them). Defined in PRC Section 21074(a), a tribal cultural resource is a CRHR or local register eligible site, feature, place, cultural landscape, or object which has a cultural value to a California Native American tribe. Tribal cultural resources must also meet the definition of a historical resource. Unique archaeological resources are referenced in PRC Section 21083.2.

PRC Section 5024 requires state agencies to identify and protect state-owned historical resources that meet the NRHP listing criteria. It further requires Caltrans to inventory state-owned structures in its rights-of-way. Sections 5024(f) and 5024.5 require state agencies to provide notice to and consult with the State Historic Preservation Officer (SHPO) before altering, transferring, relocating, or demolishing state-owned historical resources that are listed on or are eligible for inclusion in the NRHP or are registered or eligible for registration as California Historical Landmarks. Procedures for compliance with PRC Section 5024 are outlined in a MOU between Caltrans and SHPO, effective January 1, 2015. For most Federal-aid projects on the State Highway System, compliance with the Section 106 PA will satisfy the requirements of PRC Section 5024.

2.9.2 Affected Environment
The information in this section is based primarily on an Archaeological Survey Report (ASR) (December 2024), Historical Resources Evaluation Report (January 2025), and a Historic Property Survey Report (HPSR) (March 2025) prepared for the Project. The ASR and HPSR contain confidential information regarding the location(s) of cultural resources and, therefore, are not available for public review.15 A copy of the HRER is available for review at the locations listed inside the front cover of this document. The studies were supported by field surveys, record searches, archival research, and consultation with local planners, historical societies, and Native American tribes. An Area of Potential Effects (APE) was established. One previously identified historical resource—the East Napa Historic District—is within the APE. The project review has been used to determine if the project would directly or indirectly alter the character or use of the district.

2.9.2.1 Archaeological Resources
The Northwest Information Center (NWIC) identified seven archaeological resources within a half-mile search radius of the Project. The previously recorded archaeological resources include Native American lithic scatter (e.g., obsidian flakes, mortars, pestles,

15 Under Federal and State laws, the archaeological reports are not public documents as they contain confidential information regarding the location(s) of cultural resources.

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bifaces, etc.), human remains, artifacts originating from Napa’s Chinatown community, historic-period dump sites, a farmhouse site, and a tannery deposit.

Tribal Consultation
A search of the Native American Heritage Commission’s (NAHC) sacred lands file was also conducted. The results were positive, indicating the potential presence of sacred lands, and NAHC provided a list of recommended tribes to consult for further information. Consultation letters were sent on August 7, 2024, by US Mail and email to 16 individuals representing eight tribal organizations. Follow-up emails were sent on September 3, 2024 to non-responsive tribes. The Muwekma Ohlone Tribe of the SF Bay Area, Mishewal-Wappo Tribe of Alexander Valley, and Yocha Dehe Wintun Nation provided responses. A tribal representative of the Muwekhma Ohlone Tribe stated that the tribe declined consultation because the Project area is outside of the tribe’s jurisdiction. Based on their requests, Caltrans and the City of Napa met with the Mishewal-Wappo Tribe of Alexander Valley on December 9, 2024, and Yocha Dehe Wintun Nation on December 16, 2024 to discuss the Project. Consultation with both tribes is ongoing.

Archaeological Sensitivity
Based on the soil composition under the Project site and the proximity to Napa River, most of the Project site has low sensitivity for buried Native American resources. The northwest corner of the proposed north roundabout (at 801 Silverado Trail and the eastern part of 820 Juarez Street) and Third Street east of Juarez Street have a moderate sensitivity for buried Native American resources. The area of Third Street west of Juarez Street is highly sensitive for prehistoric buried archaeological resources.

Prior to the 1870s, the APE was part of the Rancho Tulocay cattle ranch and Silverado Trail had already existed for hundreds of years as a path through the valley. Cattle ranching and transportation corridors are not likely to produce archaeological deposits with information potential. The Project would largely be confined to the road right-of- way, with some minor acquisitions at the Marble and Granite Works property and a full property acquisition at 801 Silverado Trail. The construction of retaining walls and sidewalks at the Marble and Granite Works property, located at 9 Coombsville Road or 1010 East Avenue, are unlikely to encounter historic-era resources because no structures from the early period of operation (1878) remain on the property. The existing residence at 801 Silverado Trail was built in 1939 and there is no evidence of prior structures. The inhabitants of the residence would have had access to municipal waste disposal and indoor plumbing throughout its history, making it unlikely that historic-era archaeological deposits would be encountered on the parcel. For these reasons, the Project site has a low sensitivity for historic-era archaeological deposits.

2.9.2.2 Historical Resources
For the purposes of this project only, the East Napa Historic District is considered eligible for the National Register of Historic Places under Criteria A, for its association with the City of Napa’s Italian American community settlement and working-class residential development, and under Criteria C, as a surviving example of a working-

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class neighborhood with high level of architectural integrity. The district contains 70 parcels, with 61 contributing resources on 55 of the district’s parcels. These properties were reviewed as part of the City of Napa’s 2010 Soscol Gateway/East Napa Historic Context Statement and Survey Report and they were recorded on Department of Parks & Recreation 523a, Primary Record forms. That earlier study did not evaluate the parcels for individual eligibility to the National Register, but applied California Historical Resource Status Code 5D3, indicating that they were recognized as historically significant by local government and that each “Appears to be a contributor to a district that appears eligible for local listing or designation through survey evaluation.” Based on the 2010 study, the district and other contributing parcels were added to the City’s Historic Resource Inventory (HRI). Eight Built Environment properties were within the APE for this project and were evaluated for NRHP eligibility. Caltrans determined that the eight properties are not individually eligible for the NRHP but is considering 820 and 802 Juarez Street, and 801 Silverado Trail to be eligible as contributors to the considered-eligible East Napa Historic District. On April 7, 2025, the SHPO concurred with Caltrans’ determinations of eligibility. The five other evaluated properties, 713 Juarez Street, 9 and 36 Coombsville Road, 1010 East Avenue, and 427 and 441 Third Street, are not individually eligible for the NRHP and are not being considered contributors to the historic district.

2.9.3 Environmental Consequences
The preferred Project alternative would result in an adverse effect to the East Napa Historic District. As a result, Caltrans District 4 Office of Cultural Resource Studies completed a HPSR and Finding of Effect (FOE) Report for the Project. Based on the studies that have been completed for the Project to date, the Project will result in a Finding of Adverse Effect, pursuant to Stipulation X.C.1 of the PA.

The SHPO stated on November 19, 2025, that they had no objection to Caltrans’s Finding of Adverse Effect for the Project. Consultation with the Section 106 Stakeholders under Section 106 continues throughout the life of the Project.

Archaeological Resources
The Project would involve ground-disturbing activities during the construction phase.

Project construction would include excavation to a depth of three to six feet for utility installation throughout the site and could include a maximum excavation depth of 10 feet to install foundations for retaining walls along Coombsville Road and East Avenue.

As previously discussed, the Project site has a low sensitivity for historic era archaeological deposits and ranges from low to high sensitivity for buried prehistoric/Native American resources. However, within much of the moderately sensitive area, the current right-of-way has been previously disturbed by utility installations along Third Street. Additionally, the grade would be raised at all of 801 Silverado Trail and the portion of 820 Juarez Street within the Project’s area of direct impact (ADI) by four to six feet. After the grade is raised, ground-disturbing activities would not affect native soils on these two parcels. Additionally, ground-disturbing work in the highly sensitive area on Third Street west of Juarez Street would be limited to asphalt reconstruction and striping and would not disturb native soils.

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Nevertheless, the Project could impact unknown archaeological resources during construction. Given that most of the Project ADI is within areas of low to moderate sensitivity and the Project would not result in ground-disturbing activities within areas of high sensitivity, implementation of Caltrans’ standard policies regarding the encounter of unidentified cultural materials during construction would ensure that no adverse effect occurs (see PF CULT-1.1 and 1.2).

Historical Resources
The Project requires the acquisition of approximately 2,140 square feet of the mostly vacant rear yard of 820 Juarez Street, adjacent to SR 121, and temporary construction easements (TCEs) from 820 Juarez Street and 802 Juarez Street, but there are no anticipated adverse effects on features of these properties that contribute to the significance of to the East Napa Historic District.

The Project also requires acquisition and demolition of 801 Silverado Trail, the Josephine and Leno Rossi House, a Mediterranean Revival style single-family residence constructed in 1939. While the residence is not individually eligible for the NRHP, it is a contributor to the East Napa Historic District, which is considered eligible for the NRHP for the purposes of this Project. Therefore, removal of the residence at 801 Silverado Trail would constitute an adverse effect on the East Napa Historic District.

The setting of the district would also be affected due to changes that would occur as part of the conversion of the intersection to two roundabouts at the southeastern corner of the district, as well as the removal of the Rossi house. On October 22, 2025, Caltrans consulted the SHPO regarding Caltrans’ finding that the project would have an adverse effect on historic properties. The SHPO responded on November 19, 2025 and did not object to the adverse effect finding. The district is a historic property protected by Section 4(f) of the Department of Transportation Act of 1966. The proposed Project would result in a “use” of those properties as defined by Section 4(f). Please see additional details in Appendix A.

No-Build Alternative
The No-Build Alternative would not affect any cultural resources.

2.9.4 Avoidance, Minimization, and/or Mitigation Measures The following measures are included in the Project for the purpose of minimizing and mitigating effects on the East Napa Historic District. With MM-CULT-1 incorporated, the project would result in less than significant effects to cultural resources. The measure's requirements include a thorough evaluation of the District's historical significance, and development, in coordination with community stakeholders, of identification and interpretive materials. These strategies are captured in a Memorandum of Agreement (MOA) negotiated by Caltrans, as the NEPA lead agency, with the stakeholders and the SHPO.

MM CULT-1.1: Historic Resource Preservation: Following construction, the Project Sponsor will prepare, in consultation with the State Historic Preservation Officer (SHPO), an evaluation of the East Napa Historic

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District for eligibility to the National Register of Historic Places. In consultation with Section 106 stakeholders and the SHPO, Caltrans and the City of Napa will implement mitigation measures specific to the effects to the East Napa Historic District, including, but not limited to, installation of identification signs and interpretive materials providing information on the history of the neighborhood and recordation of 801 Silverado Trail consistent with the Historic American Building Survey (HABS) standards maintained in local repositories. These mitigation measures are captured in a Memorandum of Agreement between Caltrans as the NEPA lead agency, the stakeholders, and the SHPO. .

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PHYSICAL ENVIRONMENT

2.10 Hydrology and Floodplain

2.10.1 Regulatory Setting
Executive Order (EO) 11988 (Floodplain Management) directs all federal agencies to refrain from conducting, supporting, or allowing actions in floodplains unless it is the only practicable alternative. The Federal Highway Administration (FHWA) requirements for compliance are outlined in 23 Code of Federal Regulations (CFR) 650 Subpart A.

To comply, the following must be analyzed:
• The practicability of alternatives to any longitudinal encroachments. • Risks of the action.
• Impacts on natural and beneficial floodplain values.
• Support of incompatible floodplain development.
• Measures to minimize floodplain impacts and to preserve/restore any beneficial floodplain values affected by the project.

The base floodplain is defined as “the area subject to flooding by the flood or tide having a one percent chance of being exceeded in any given year.” An encroachment is defined as “an action within the limits of the base floodplain.”

2.10.2 Affected Environment
The information in this section is based primarily on a Location Hydraulic Study (January 2025) prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

The Project site is depicted on the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map panel number 06055C0517F. As shown in Figure 2.10-1, the portion of the Project site located near the Napa River is within the Zone AE Floodplain.

Zone AE is defined as a special flood hazard area with one percent chance of flooding in any given year. A portion of the Project site is also located within an area with a 0.2 percent chance of flooding in any given year. The rest of the Project site is located within Flood Zone X, an area of minimal flood hazard. FEMA’s 100-year water base flood elevation (BFE) at the Project site is 18.99 feet.

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2.10.3 Environmental Consequences
The FHWA defines a significant floodplain encroachment as a highway encroachment, and any direct support of likely base floodplain development, that would involve one or more of the following construction or flood-related impacts: 1) significant potential for interruption or termination of a transportation facility that is needed for emergency vehicles or provides a community’s only evacuation route, 2) a significant risk with change in land use, fill inside the floodplain, or change in water surface elevation, or 3) a significant adverse impact on the natural and beneficial floodplain values. Natural and beneficial floodplain values include, but are not limited to fish, wildlife, plants, open space, natural beauty, scientific study, outdoor recreation, agriculture, aquaculture, forestry, natural moderation of floods, water quality maintenance, and groundwater recharge.

The Project encroaches into the base floodplain associated with the Napa River Oxbow Overflow Channel. The Project would add fill within the floodplain along Third Street, resulting in a final grade of approximately 23.8 feet (4.81 feet above the BFE). The Location Hydraulic Study determined the Project would not impact the water surface elevation or change the channel velocity. Therefore, the Project would not cause property damage to upstream or downstream reaches of the Project area. The proposed roadway would also not be overtopped during a 100-year design storm event and, therefore, there is no potential for damage to the proposed improvements, interruption of traffic, or loss of life due to flooding during the service life of the Project.

Potential short-term adverse effects to the natural and beneficial floodplain values during Project construction and their AMMs are described in Section 2.11 Water Quality and Stormwater Runoff, Section 2.18 Natural Communities, and 2.20 Threatened and Endangered Species.

For these reasons, the Project is not considered a significant encroachment as it does not involve significant potential for interruption or termination of a transportation facility that is needed for emergency vehicles or provides a community’s only evacuation route, a significant risk, or cause a significant adverse impact to the natural and beneficial floodplain values.

No-Build Alternative
The No-Build Alternative would not make any changes to the existing floodplain. The existing grade would remain at the same elevation, leaving the roadway along Third Street susceptible to flooding during flood events.

2.10.4 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, and/or mitigation measures are required.

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2.11 Water Quality and Stormwater Runoff

2.11.1 Regulatory Setting

2.11.1.1 Federal Requirements: Clean Water Act
In 1972, Congress amended the Federal Water Pollution Control Act, making the addition of pollutants to the waters of the United States (U.S.) from any point source16 unlawful unless the discharge is in compliance with a National Pollutant Discharge Elimination System (NPDES) permit. This act and its amendments are known today as the Clean Water Act (CWA). Congress has amended the act several times. In the 1987 amendments, Congress directed dischargers of storm water from municipal and industrial/construction point sources to comply with the NPDES permit scheme. The following are important CWA sections:
• Sections 303 and 304 require states to issue water quality standards, criteria, and guidelines.
• Section 401 requires an applicant for a federal license or permit to conduct any activity that may result in a discharge to waters of the U.S. to obtain certification from the state that the discharge will comply with other provisions of the act. This is most frequently required in tandem with a Section 404 permit request (see below).
• Section 402 establishes the NPDES, a permitting system for the discharges (except for dredge or fill material) of any pollutant into waters of the U.S.

Regional Water Quality Control Boards (RWQCBs) administer this permitting program in California. Section 402(p) requires permits for discharges of storm water from industrial/construction and municipal separate storm sewer systems (MS4s).
• Section 404 establishes a permit program for the discharge of dredge or fill material into waters of the U.S. This permit program is administered by the U.S.

Army Corps of Engineers (USACE).

The goal of the CWA is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”
The USACE issues two types of 404 permits: General and Individual. There are two types of General permits: Regional and Nationwide. Regional permits are issued for a general category of activities when they are similar in nature and cause minimal environmental effect. Nationwide permits are issued to allow a variety of minor project activities with no more than minimal effects.

Ordinarily, projects that do not meet the criteria for a Regional or Nationwide Permit may be permitted under one of the USACE’s Individual permits. There are two types of Individual permits: Standard permits and Letters of Permission. For Individual permits, the USACE decision to approve is based on compliance with U.S. Environmental Protection Agency’s (U.S. EPA) Section 404 (b)(1) Guidelines (40 Code of Federal 16 A point source is any discrete conveyance such as a pipe or a man-made ditch.

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Regulations [CFR] Part 230), and whether the permit approval is in the public interest.

The Section 404(b)(1) Guidelines (Guidelines) were developed by the U.S. EPA in conjunction with the USACE, and allow the discharge of dredged or fill material into the aquatic system (waters of the U.S.) only if there is no practicable alternative which would have less adverse effects. The Guidelines state that the USACE may not issue a permit if there is a least environmentally damaging practicable alternative (LEDPA) to the proposed discharge that would have lesser effects on waters of the U.S. and not have any other significant adverse environmental consequences. According to the Guidelines, documentation is needed that a sequence of avoidance, minimization, and compensation measures has been followed, in that order. The Guidelines also restrict permitting activities that violate water quality or toxic effluent17 standards, jeopardize the continued existence of listed species, violate marine sanctuary protections, or cause “significant degradation” to waters of the U.S. In addition, every permit from the USACE, even if not subject to the Section 404(b)(1) Guidelines, must meet general requirements. See 33 CFR 320.4.

2.11.1.2 State Requirements: Porter-Cologne Water Quality Control Act California’s Porter-Cologne Act, enacted in 1969, provides the legal basis for water quality regulation within California. This act requires a “Report of Waste Discharge” for any discharge of waste (liquid, solid, or gaseous) to land or surface waters that may impair beneficial uses for surface and/or groundwater of the state. It predates the CWA and regulates discharges to waters of the state. Waters of the State include more than just waters of the U.S., like groundwater and surface waters not considered waters of the U.S. Additionally, it prohibits discharges of “waste” as defined, and this definition is broader than the CWA definition of “pollutant.” Discharges under the Porter-Cologne Act are permitted by Waste Discharge Requirements (WDRs) and may be required even when the discharge is already permitted or exempt under the CWA.

The State Water Resources Control Board (SWRCB) and RWQCBs are responsible for establishing the water quality standards (objectives and beneficial uses) required by the CWA and regulating discharges to ensure compliance with the water quality standards.

Details about water quality standards in a project area are included in the applicable RWQCB Basin Plan. In California, RWQCBs designate beneficial uses for all water body segments in their jurisdictions and then set criteria necessary to protect those uses. As a result, the water quality standards developed for particular water segments are based on the designated use and vary depending on that use. In addition, the SWRCB identifies waters failing to meet standards for specific pollutants. These waters are then state-listed in accordance with CWA Section 303(d). If a state determines that waters are impaired for one or more constituents and the standards cannot be met through point source or non-point source controls (NPDES permits or WDRs), the CWA requires the establishment of Total Maximum Daily Loads (TMDLs). TMDLs specify allowable pollutant loads from all sources (point, non-point, and natural) for a given watershed.
17 The U.S. EPA defines “effluent” as “wastewater, treated or untreated, that flows out of a treatment plant, sewer, or industrial outfall.”

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State Water Resources Control Board and Regional Water Quality Control Boards The SWRCB administers water rights, sets water pollution control policy, and issues water board orders on matters of statewide application, and oversees water quality functions throughout the state by approving Basin Plans, TMDLs, and NPDES permits.

RWCQBs are responsible for protecting beneficial uses of water resources within their regional jurisdiction using planning, permitting, and enforcement authorities to meet this responsibility.

2.11.1.3 National Pollutant Discharge Elimination System (NPDES) Program Municipal Separate Storm Sewer Systems (MS4)
Section 402(p) of the CWA requires the issuance of NPDES permits for five categories of storm water discharges, including Municipal Separate Storm Sewer Systems (MS4s).

An MS4 is defined as “any conveyance or system of conveyances (roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, human-made channels, and storm drains) owned or operated by a state, city, town, county, or other public body having jurisdiction over storm water, that is designed or used for collecting or conveying storm water.” The SWRCB has identified Caltrans as an owner/operator of an MS4 under federal regulations. Caltrans MS4 permit covers all Department rights-of- way, properties, facilities, and activities in the state. The SWRCB or the RWQCB issues NPDES permits for five years, and permit requirements remain active until a new permit has been adopted.

The Caltrans’ MS4 Permit, Order No. 2022-0033-DWQ (adopted on June 22, 2022 and effective on January 1, 2023) has three basic requirements:

1. Caltrans must comply with the requirements of the Construction General Permit (see below);

2. Caltrans must implement a year-round program in all parts of the State to effectively control storm water and non-storm water discharges; and

3. Caltrans storm water discharges must meet water quality standards through implementation of permanent and temporary (construction) Best Management Practices (BMPs), to the maximum extent practicable, and other measures as the SWRCB determines to be necessary to meet the water quality standards.

To comply with the permit, Caltrans developed the Statewide Storm Water Management Plan (SWMP) to address storm water pollution controls related to highway planning, design, construction, and maintenance activities throughout California. The SWMP assigns responsibilities within Caltrans for implementing storm water management procedures and practices as well as training, public education and participation, monitoring and research, program evaluation, and reporting activities. The SWMP describes the minimum procedures and practices Caltrans uses to reduce pollutants in storm water and non-storm water discharges. It outlines procedures and responsibilities for protecting water quality, including the selection and implementation of BMPs. The proposed Project will be programmed to follow the guidelines and procedures outlined in the latest SWMP to address storm water runoff.

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Construction General Permit
Construction General Permit, Order No. 2022-0057-DWQ was adopted on September 8, 2022, and became effective on September 1, 2023. The permit regulates storm water discharges from construction sites that result in a Disturbed Soil Area (DSA) of one acre or greater, and/or are smaller sites that are part of a larger common plan of development. By law, all storm water discharges associated with construction activity where clearing, grading, and excavation result in soil disturbance of at least one acre must comply with the provisions of the General Construction Permit. Construction activity that results in soil disturbances of less than one acre is subject to this Construction General Permit if there is potential for significant water quality impairment resulting from the activity as determined by the RWQCB. Operators of regulated construction sites are required to develop Storm Water Pollution Prevention Plans (SWPPPs); to implement sediment, erosion, and pollution prevention control measures; and to obtain coverage under the Construction General Permit.

The Construction General Permit separates projects into Risk Levels 1, 2, or 3. Risk levels are determined during the planning and design phases, and are based on potential erosion and transport to receiving waters. Requirements apply according to the Risk Level determined. For example, a Risk Level 3 (highest risk) project would require compulsory storm water runoff pH and turbidity monitoring, and before construction and after construction aquatic biological assessments during specified seasonal windows.

For all projects subject to the permit, applicants are required to develop and implement an effective SWPPP. In accordance with Caltrans’s SWMP and Standard Specifications, a Water Pollution Control Program (WPCP) is necessary for projects with DSA less than one acre.

2.11.2 Affected Environment
The information in this section is based primarily on a Hydrology and Water Quality Memorandum (September 2024), a Drainage Technical Memorandum (August 2024), and a Stormwater Data Report (October 2024) which are incorporated into this Final EIR/EA by reference. These reports are available for review at the locations listed inside the front cover of this document.

The Project site is located within the Tulucay Creek-Frontal San Pablo Bay Estuaries Watershed. There are no surface waters (e.g., creeks, streams, rivers, lakes, or other water bodies) located within the Project limits. The Napa River is the receiving water body for storm water drainage in the Project area. The Napa River is located to the northwest of the Project site and is adjacent to the north side of the proposed construction staging area. The Napa River is on the U.S. EPA’s 303(d) list of impaired water bodies due to nuisance algae growth caused by the excessive concentrations of nutrients.18 Total Maximum Daily Loads (TMDLs) for the Napa River have been established for nutrients and pathogens.
18 California State Water Resources Control Board. 2024 California Integrated Report. March 2024.

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2.11.3 Environmental Consequences
Short-Term/Construction Phase Effects
Construction of the Project would require demolition of existing pavement, excavation for retaining wall foundations, trenching, grading, and paving. In addition, construction materials and equipment would be moved on- and off-site as necessary for the duration of construction. These construction activities would temporarily increase the amount of unconsolidated materials on-site, and grading activities could increase erosion and sedimentation that could be carried by runoff into the Napa River. The Napa River is a 303(d) listed waterbody, however, sediment is not a listed pollutant of concern for the river. Therefore, the Project was determined to have low risk for sediment impacts.

Nevertheless, because construction activities could increase sedimentation and pollutant loads, the project would be required to develop and implement BMPs to control erosion and sedimentation during construction. The project sponsor would be required to comply with the state’s Construction General Permit for Storm Water Discharges Associated with Construction Activity. This entails filing a Notice of Intent, paying a filing fee, and preparing and implementing a site-specific SWPPP (which includes both construction-stage and post-construction BMPs for stormwater quality protection).

Preparation of and compliance with a SWPPP as part of the NPDES program is mandated by state and federal statutes. Construction activities would not result in substantial adverse water quality effects as a result.

Long-Term/Operational Phase Effects
The Project would result in approximately 0.30 acres (13,068 square feet) of net new impervious surface and a disturbed surface area (DSA) of 2.75 acres. The Project is subject to compliance with the NPDES General Permit and because the Project would result in a DSA of more than one acre, a SWPPP will be required. Because the Project would result in over 10,000 square feet of net new impervious surface area, the Project would also be required to implement stormwater treatment best management practices (TBMPs) to capture pollutants from roadway runoff, consistent with the NPDES General Permit and Section 404 and 401 of the CWA. The Project limits are within an area of low trash generation,19 therefore, no trash capture devices are required to be implemented as part of the stormwater infrastructure.

No-Build Alternative
The No-Build Alternative would not result in any new sources of water pollutants. No stormwater treatment controls would be added to the Project site under the No-Build Alternative.
19 California Department of Transportation. District 4 Regional Board 2 Trash Generation Map. Accessed January 14, 2026.
https://giswest.mbakerintl.com/bakerportal/apps/webappviewer/index.html?id=72277c8d263749e9b52c88 49a6fe8730

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2.11.4 Avoidance, Minimization, and/or Mitigation Measures The following measures are included in the Project for the purpose of avoiding and minimizing the water quality effects of the Project.

AMM WQ-1.1: Prior to any soil disturbance work, file a Notice of Intent with State Water Resources Control Board (SWRCB). To maintain proper permit coverage under the Construction Stormwater General Permit (CGP), in addition to filing a Notice of Intent, all dischargers must electronically file permit registration documents, Notice of Termination, changes of information, sampling and monitoring information, annual reporting, and other required compliance documents through the SWRCB’s Stormwater Multiple Application and Report Tracking System (SMARTS).

AMM WQ-1.2: Prepare and implement a Stormwater Pollution Prevention Plan (SWPPP). Prior to the start of construction, the SWPPP would be submitted by the Contractor to Caltrans for approval. The SWPPP shall detail the measures to address the temporary water quality impacts resulting from construction activities associated with this Project. The SWPPP shall also include the development of a Construction Site Monitoring Program that presents procedures and methods related to the visual monitoring, sampling, and analysis plans during construction of the Project.

Additionally, the treatment BMP certifications will be prepared and provided at various milestones of the Project.

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2.12 Geology/Soils/Seismic/Topography

2.12.1 Regulatory Setting
For geologic and topographic features, the key federal law is the Historic Sites Act of 1935, which establishes a national registry of natural landmarks and protects “outstanding examples of major geological features.” Topographic and geologic features are also protected under the California Environmental Quality Act (CEQA).

This section also discusses geology, soils, and seismic concerns as they relate to public safety and project design. Earthquakes are prime considerations in the design and retrofit of structures. Structures are designed using Caltrans’s Seismic Design Criteria (SDC). The SDC provides the minimum seismic requirements for highway bridges designed in California. A bridge’s category and classification will determine its seismic performance level and which methods are used for estimating the seismic demands and structural capabilities. For more information, please see the Caltrans Division of Engineering Services, Office of Earthquake Engineering, Seismic Design Criteria.20

2.12.2 Affected Environment
The information in this section is based primarily on a Preliminary Geotechnical Design Report (August 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

The Project site is in the Coast Ranges Geomorphic Province in the Napa River Valley.

The site is mapped to be underlain by Holocene stream terraces and Early to Late Pleistocene alluvial deposits. Both the Holocene and Pleistocene units are composed of sand, gravel, silt, and clay. Bedrock at the eastern side of the Project limits, where the topography starts to rise, is likely within a few feet of the surface and composed of Pliocene, and late Miocene tuff breccia of the Sonoma Volcanics.

Two borings were completed on-site by Parikh Consultants, Inc., one for each proposed retaining wall. One boring was taken to a depth of 31 feet below ground surface (bgs) and one boring was taken to a depth of 29 feet bgs. The boring samples were classified and tested to establish the existing geologic conditions and potential geologic hazards that could occur on-site.

The San Francisco Bay Area is one of the most seismically active areas of North America and is influenced by the San Andreas fault system, which spans the Coast Ranges from the Pacific Ocean to the San Joaquin Valley and includes the West Napa fault. The closest active fault to the Project site is the West Napa fault, located approximately two miles to the west and southwest of the project limits. The Project site is susceptible to strong earthquake-induced ground shaking. However, the site is not located within an Alquist-Priolo Fault Zone and thus, is not susceptible to fault rupture. 20 https://dot.ca.gov/programs/engineering-services/manuals/seismic-design-criteria.

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Liquefaction occurs when saturated cohesionless soils are subject to a temporary but essentially total loss of shear strength under the reversing, cyclic shear stresses associated with earthquake shaking. Both borings did not encounter groundwater before encountering bedrock, therefore, the potential for liquefaction does not exist based on the boring data collected on-site. However, bedrock is expected to be deeper along SR 121 based on available data from other studies and the site topography. Additional borings would be required to verify liquefaction potential.

A consequence of seismic liquefaction in sloping ground areas is lateral spreading, which is the movement of ground laterally after the loss of support due to liquefaction.

For this to occur, the liquefied soils must be close to a free face (e.g., an unsupported, vertical, or sloping face) such as a road cut or stream/riverbank. As previously discussed, the boring data suggests that there is no potential for liquefaction at the site and therefore, there would also be no potential for lateral spreading. However, the potential for lateral spreading would need to be reviewed when additional data becomes available.

The majority of the Project limits is mapped as having low potential for landslides due to the relatively flat nature of the topography.21 The Tulocay Cemetery, adjacent to the east of the Project limits, is mapped as having moderate potential for landslides.

The expansive potential is the ability of soils with a high clay content to change volume with moisture content. The majority of soils in the Project area have low expansive potential.22 The western section of the Project limits is mapped as having moderate expansive potential. Collapsible soils are typically associated with arid and semi-arid regions. Specific soil types such as loess and other fine-grained aeolian soils are most susceptible to collapse, although certain coarser-grained and rapidly deposited alluvial soils can also be susceptible. Some soils may fit the criteria, such as rapidly deposited coarse-grained soils. However, the soil collapse potential is considered low within the Project limits based on the boring data taken on-site.

2.12.3 Environmental Consequences
As previously discussed, the Project site is located within the seismically active San Francisco Bay region, but it is not located within an Alquist-Priolo Fault Zone. There are no known earthquake faults crossing the Project limits; therefore, the site is not subject to ground rupture. The Project site would be subject to strong ground-shaking in the event of an earthquake, particularly from one located along the West Napa Fault. Users of the proposed roundabouts would be exposed to hazards associated with such severe ground shaking during a major earthquake on one of the region's active faults. This hazard is not unique to the Project, because it applies to all locations throughout the greater Bay Area. The proposed Project will not increase the existing exposure to 21 United States Geological Survey. U.S. Landslide Inventory and Susceptibility Map. Accessed February 6, 2025.
https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=ae120962f459434b8c904b456c82669d 22 United State Department of Agriculture, Natural Resources Conservation Service. “Soil Survey Geographic (SSURGO) Database for Napa County, California, Western Part, ca055”. 2019.

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hazards associated with earthquakes; the hazards in the area will be the same with or without the Project.

The majority of the Project site has low potential for landslides due to its relatively flat nature. Based on the boring data collected on-site by Parikh Consultants, Inc., there does not appear to be potential for liquefaction because groundwater was not encountered above bedrock in the samples taken. However, more samples would need to be taken to verify liquefaction potential on-site, as bedrock elevations are expected to be deeper along SR 121. Additional exploration and testing during the Plans Specifications and Estimates (PS&E) phase will be completed to confirm site-specific liquefaction potential. The Project will implement standard engineering practices to ensure that geotechnical and soil hazards do not result from its construction.

The Project, including the roundabouts and retaining walls will be designed and constructed in accordance with Caltrans’ Design guidelines for Seismic Zone 4 to avoid or minimize potential damage from seismic shaking on the site. Potential seismic effects will be minimized by the use of standard engineering techniques mandated by the Uniform Building Code and Caltrans’ Design Standards.

No-Build Alternative
The No-Build Alternative would not introduce any new infrastructure to the Project site.

2.12.4 Avoidance, Minimization, and/or Mitigation Measures As discussed in the previous section, the Project would be designed to comply with both the Uniform Building Code and Caltrans’ Design Standards. In addition, some of the measures that will minimize or avoid impacts to water quality will also serve to minimize or avoid impacts associated with erosion. For a list of these measures, please see Section 2.11 Water Quality and Stormwater Runoff. During the Project design phase, the following measure shall be required to verify liquefaction potential at the site and avoid and minimize any potential effects related to liquefaction.

AMM GEO-1.1: At minimum, one additional boring shall be drilled at the location of the proposed retaining wall along the west side of East Avenue at the SR 121 level to verify the subsoil/groundwater conditions and bedrock depths. An additional boring shall be drilled at the location of the proposed retaining wall along the northeast side of Coombsville Road on the western end of the proposed wall. Additional laboratory tests shall also include moisture content, unit weight, plasticity indexes and liquid limits, particle size analyses, consolidation, strength tests, and corrosivity testing.

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2.13 Paleontology

2.13.1 Regulatory Setting
Paleontology is a natural science focused on the study of ancient animal and plant life as it is preserved in the geologic record as fossils.

A number of federal statutes specifically address paleontological resources, their treatment, and funding for mitigation as a part of federally authorized projects. • 23 United States Code (USC) 1.9(a) requires that the use of Federal-aid funds must be in conformity with all federal and state laws.
• 23 United States Code (USC) 305 authorizes the appropriation and use of federal highway funds for paleontological salvage as necessary by the highway department of any state, in compliance with 16 USC 431-433 above and state law.

Under California law, paleontological resources are protected by the California Environmental Quality Act (CEQA).

2.13.2 Affected Environment
The majority of the City of Napa is underlain by Holocene alluvium and alluvial fan deposits, which are likely too young to contain fossils.23 However, Napa also has Pleistocene, Pliocene, and Miocene deposits that are comprised of the Sonoma Volcanics and the Great Valley Sequence. These geologic units are generally considered paleontologically sensitive because they have demonstrated recovery of significant fossils. A search of paleontological records maintained by the University of California Museum of Paleontology indicated no vertebrate fossils or other paleontological resources have been recovered within 10 miles of the Project site.

2.13.3 Environmental Consequences
While the City of Napa is generally underlain by Holocene deposits with low paleontological sensitivity, the site also is underlain by Early to Late Pleistocene alluvial deposits. Bedrock at the eastern side of the Project limits, where the topography starts to rise, is likely within a few feet of the surface and composed of Pliocene, and late Miocene tuff breccia of the Sonoma Volcanics, a known paleontologically sensitive geologic unit. Based on the lack of known paleontological resources within 10 miles of the Project site and the level of ground disturbance required by the Project, it is unlikely that construction would encounter any undisturbed pre-Holocene sediments with fossils.

No-Build Alternative
The No-Build Alternative would not affect any paleontological resources. 23 City of Napa. General Plan Update EIR. March 2022. P. 3.6-16.

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2.13.4 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, and/or mitigation measures are required.

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2.14 Hazardous Waste/Materials

2.14.1 Regulatory Setting
Hazardous materials, including hazardous substances and wastes, are regulated by many state and federal laws. Statutes govern the generation, treatment, storage, and disposal of hazardous materials, substances, and waste, and also the investigation and mitigation of waste releases, air and water quality, human health, and land use.

The primary federal laws regulating hazardous wastes/materials are the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, and the Resource Conservation and Recovery Act (RCRA) of 1976 (RCRA). The purpose of CERCLA, often referred to as “Superfund,” is to identify and cleanup abandoned contaminated sites so that public health and welfare are not compromised. The RCRA provides for “cradle to grave” regulation of hazardous waste generated by operating entities. Other federal laws include:
• Community Environmental Response Facilitation Act (CERFA) of 1992 • Clean Water Act
• Clean Air Act
• Safe Drinking Water Act
• Occupational Safety and Health Act (OSHA)
• Atomic Energy Act
• Toxic Substances Control Act (TSCA)
• Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) In addition to the acts listed above, Executive Order (EO) 12088, Federal Compliance with Pollution Control Standards, mandates that necessary actions be taken to prevent and control environmental pollution when federal activities or federal facilities are involved.

California regulates hazardous materials, waste, and substances under the authority of the CA Health and Safety Code and is also authorized by the federal government to implement RCRA in the state. California law also addresses specific handling, storage, transportation, disposal, treatment, reduction, cleanup, and emergency planning of hazardous waste. The Porter-Cologne Water Quality Control Act also restricts disposal of wastes and requires cleanup of wastes that are below hazardous waste concentrations but could impact ground and surface water quality. California regulations that address waste management and prevention and cleanup of contamination include Title 22 Division 4.5 Environmental Health Standards for the Management of Hazardous Waste, Title 23 Waters, and Title 27 Environmental Protection.

Worker and public health and safety are key issues when addressing hazardous materials that may affect human health and the environment. Proper management and disposal of hazardous material is vital if it is found, disturbed, or generated during project construction.

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2.14.2 Affected Environment
The information in this section is based primarily on an Initial Site Assessment (May 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

Prior to 1992, lead was commonly added to gasoline in California.24 Aerially deposited lead (ADL) is a common hazardous material found along highways due to vehicle tailpipe exhaust when lead was formerly a constituent of gasoline. It is likely that ADL is present on and adjacent to the existing roadway. Based on the 1939 construction date, there is potential for the presence of asbestos25 containing materials (ACMs) and lead based paint (LBP) associated with the residential building at 801 Silverado Trail. The existing roadway materials could also contain LBP.

A database record search was conducted to review regulatory agency lists in order to identify the presence of hazardous waste sites within a one-mile radius of the project alignment. The purpose of the regulatory database search is 1) to identify sites with known or potential contamination from hazardous materials, and 2) to determine if any of those sites might adversely affect the proposed intersection improvements. Four sites were identified as having the potential to adversely affect the Project site. These sites are described below:
• Caltrans Construction: Inorganic solid waste was generated from Caltrans construction within the project intersection in 2010. The waste was removed by landfill or surface impoundment through on-site treatment and/or stabilization.

Waste generated by this construction occurred over 10 years ago and the waste removal has been completed.
• Beacon/Texaco: There is a leaking underground storage tank (LUST) cleanup site at 713 Silverado Trail, adjacent to the Project limits associated with a former Texaco service station (currently Napa Tire and Wheels). A leaking gasoline storage tank was removed from the site in 1990 and the groundwater in the vicinity was monitored until the Napa County Department of Public Works issued a case closure letter in 2013 declaring that no further action was required. The cleanup site is located cross-gradient from the Project limits. • Tulocay Cemetery Association: Tulocay Cemetery Association, located adjacent to the east of the Project limits, had several diesel fuel containers.

There are no recorded chemical spills associated with the cemetery, which is located up-gradient from the project limits.
24 Lead is a heavy metal that is found in many products. Lead is poisonous to humans. It is especially toxic to the nervous system, although it can adversely affect many systems and organs. In recent years, lead has been removed from certain products such as paint and gasoline in order to reduce the potential for chronic exposure.
25 Asbestos is a mineral that is found in many products because of its resistance to damage from chemicals and heat, as well as its noise absorption properties. However, asbestos is toxic, especially when inhaled. It can cause diseases such as lung cancer, mesothelioma, and asbestosis.

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• Napa Pacific Associates A California L.P.: In 2018, Napa Pacific Associates A California L.P was found to generate waste containing asbestos along Coombsville Road, approximately 700 feet east of the Project limits. The waste was removed by landfill or surface impoundment through on-site treatment and/or stabilization. The cleanup has since been completed. No violations have been reported within the last five years, and the status is now closed.

Utility poles, roadside wooden signposts, or metal beam guardrail posts within the Project limits may include chemically treated wood and may be disturbed by the construction of the Project.

2.14.3 Environmental Consequences
LBP, ADL, and/or ACMs are likely present within the Project footprint. As such, various construction activities could expose workers to these substances, which could result in adverse health impacts. Such exposure will be avoided by implementing PF HM-1.1 through 1.3 and the AMMs described below.

Treated wood waste in the Project area could include existing utility poles, roadside wooden signposts, or metal beam guardrail posts removed by the Project. Treated wood waste will be handled properly in accordance with applicable Caltrans guidelines and if warranted, will require special removal, handling, and disposal.

No-Build Alternative
The No-Build Alternative would not expose workers to potentially hazardous materials.

The existing roadway infrastructure and residential structure would remain in place.

2.14.4 Avoidance, Minimization, and/or Mitigation Measures The Project will implement the following measures during final design and construction to avoid impacts associated with exposing construction workers to unsafe levels of hazardous substances:

AMM HM-1.1: Testing for the presence of lead-based paint and asbestos-containing materials, on the existing structure at 801 Silverado Trail and roadway paint to be removed shall occur. If these substances are found to be present, applicable regulations pertaining to their removal and disposal shall be followed.

AMM HM-1.2: Testing of the soils within the project area for worker safety and soil management purposes shall occur. Soils and groundwater, if encountered, shall be tested for the following:
• Total petroleum hydrocarbons (TPH) as gasoline, as diesel, and as motor oil;
• Pesticides and herbicides;
• CAM 17 metals

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The costs for sampling, testing, special handling, and disposal of potentially hazardous materials are unknown at this stage of preliminary design and environmental review. It is estimated that costs could range from $75,000 to $100,000 or more depending on the number of samples collected, the laboratory analyses used, and quantity of material that requires special disposal. The costs for special handling, if required, of contaminated building materials from 801 Silverado Trail has to be removed would be estimated during final design.

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2.15 Air Quality

2.15.1 Regulatory Setting
The Federal Clean Air Act (FCAA), as amended, is the primary federal law that governs air quality while the California Clean Air Act (CCAA) is its companion state law. These laws, and related regulations by the United States Environmental Protection Agency (U.S. EPA) and the California Air Resources Board (ARB), set standards for the concentration of pollutants in the air. At the federal level, these standards are called National Ambient Air Quality Standards (NAAQS). NAAQS and state ambient air quality standards have been established for six criteria pollutants that have been linked to potential health concerns: carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), particulate matter (PM) – which is broken down for regulatory purposes into particles of 10 micrometers or smaller (PM10) and particles of 2.5 micrometers and smaller (PM2.5), Lead (Pb), and sulfur dioxide (SO2). In addition, state standards exist for visibility reducing particles, sulfates, hydrogen sulfide (H2S), and vinyl chloride. Table 2.15-1 lists primary air pollutants, their effects on health and the environment, and their typical sources. The NAAQS and state standards are set at levels that protect public health with a margin of safety and are subject to periodic review and revision. Both state and federal regulatory schemes also cover toxic air contaminants (air toxics); some criteria pollutants are also air toxics or may include certain air toxics in their general definition.

Table 2.15-1: Air Pollutant Effects and Sources
Pollutant Principal Health and Atmospheric
Effects Typical Sources
Ozone (O3)
High concentrations irritate lungs. Long-
term exposure may cause lung tissue
damage and cancer. Long-term exposure
damages plant materials and reduces
crop productivity. Precursor organic
compounds include many known toxic air
contaminants. Biogenic VOC may also
contribute.

Low-altitude ozone is almost entirely
formed from reactive organic gases/volatile
organic compounds (ROG or VOC) and
nitrogen oxides (NOx) in the presence of
sunlight and heat. Common precursor
emitters include motor vehicles and other
internal combustion engines, solvent
evaporation, boilers, furnaces, and
industrial processes.

Carbon
Monoxide (CO)
CO interferes with the transfer of oxygen
to the blood and deprives sensitive tissues
of oxygen. CO also is a minor precursor
for photochemical ozone. Colorless,
odorless.

Combustion sources, especially gasoline-
powered engines and motor vehicles. CO
is the traditional signature pollutant for on-
road mobile sources at the local and
neighborhood scale.

Respirable
Particulate Matter
(PM10)
Irritates eyes and respiratory tract.

Decreases lung capacity. Associated with
increased cancer and mortality.

Contributes to haze and reduced visibility.

Includes some toxic air contaminants.

Many toxic & other aerosol and solid
compounds are part of PM10.

Dust- and fume-producing industrial and
agricultural operations; combustion smoke
& vehicle exhaust; atmospheric chemical
reactions; construction and other dust-
producing activities; unpaved road dust
and re-entrained paved road dust; natural
sources.

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Pollutant Principal Health and Atmospheric
Effects Typical Sources
Fine Particulate
Matter (PM2.5)
Increases respiratory disease, lung
damage, cancer, and premature death.

Reduces visibility and produces surface
soiling. Most diesel exhaust particulate
matter – a toxic air contaminant – is in the
PM2.5 size range. Many toxic &other
aerosol and solid compounds are part of
PM2.5
Combustion including motor vehicles, other
mobile sources, and industrial activities;
residential and agricultural burning; also
formed through atmospheric chemical and
photochemical reactions involving other
pollutants including NOx, sulfur oxides
(SOx), ammonia, and ROG.

Nitrogen Dioxide
(NO2)
Irritating to eyes and respiratory tract.

Colors atmosphere reddish-brown.

Contributes to acid rain & nitrate
contamination of stormwater. Part of the
“NOx” group of ozone precursors.

Motor vehicles and other mobile or
portable engines, especially diesel;
refineries; industrial operations.

Sulfur Dioxide
(SO2)
Irritates respiratory tract; injures lung
tissue. Can yellow plant leaves.

Destructive to marble, iron, steel.

Contributes to acid rain. Limits visibility.

Fuel combustion (especially coal and high-
sulfur oil), chemical plants, sulfur recovery
plants, metal processing; some natural
sources like active volcanoes. Limited
contribution possible from heavy-duty
diesel vehicles if ultra-low sulfur fuel not
used.

Lead (Pb)
Disturbs gastrointestinal system. Causes
anemia, kidney disease, and
neuromuscular and neurological
dysfunction. Also a toxic air contaminant
and water pollutant.

Lead-based industrial processes like
battery production and smelters. Lead
paint, leaded gasoline. Aerially deposited
lead from older gasoline use may exist in
soils along major roads.

Sulfates
Premature mortality and respiratory
effects. Contributes to acid rain. Some
toxic air contaminants attach to sulfate
aerosol particles.

Industrial processes, refineries and oil
fields, mines, natural sources like volcanic
areas, salt-covered dry lakes, and large
sulfide rock areas.

Hydrogen Sulfide
(H2S)
Colorless, flammable, poisonous.

Respiratory irritant. Neurological damage
and premature death. Headache, nausea.

Strong odor.

Industrial processes such as: refineries
and oil fields, asphalt plants, livestock
operations, sewage treatment plants, and
mines. Some natural sources like volcanic
areas and hot springs.

Visibility
Reducing
Particles (VRP)
Reduces visibility. Produces haze. NOTE:
not directly related to the Regional Haze
program under the Federal Clean Air Act,
which is oriented primarily toward visibility
issues in National Parks and other “Class
I” areas. However, some issues and
measurement methods are similar.

See particulate matter above. May be
related more to aerosols than to solid
particles.

Vinyl Chloride
Neurological effects, liver damage,
cancer. Also considered a toxic air
contaminant.

Industrial processes

Federal air quality standards and regulations provide the basic scheme for project-level air quality analysis under the National Environmental Policy Act (NEPA). In addition to this environmental analysis, a parallel “Conformity” requirement under the FCAA also applies.

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Conformity
The conformity requirement is based on FCAA Section 176(c), which prohibits the U.S.

Department of Transportation (USDOT) and other federal agencies from funding, authorizing, or approving plans, programs, or projects that do not conform to State Implementation Plan (SIP) for attaining the NAAQS. “Transportation Conformity” applies to highway and transit projects and takes place on two levels: the regional (or planning and programming) level and the project level. The proposed project must conform at both levels to be approved.

Conformity requirements apply only in nonattainment and “maintenance” (former nonattainment) areas for the NAAQS, and only for the specific NAAQS that are or were violated. U.S. EPA regulations at 40 Code of Federal Regulations (CFR) 93 govern the conformity process. Conformity requirements do not apply in unclassifiable/attainment areas for NAAQS and do not apply at all for state standards regardless of the status of the area.

Regional conformity is concerned with how well the regional transportation system supports plans for attaining the NAAQS for carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), particulate matter (PM10 and PM2.5), and in some areas (although not in California), sulfur dioxide (SO2). California has nonattainment or maintenance areas for all of these transportation-related “criteria pollutants” except SO2, and also has a nonattainment area for lead (Pb); however, lead is not currently required by the FCAA to be covered in transportation conformity analysis. Regional conformity is based on emission analysis of Regional Transportation Plans (RTPs) and Federal Transportation Improvement Programs (FTIPs) that include all transportation projects planned for a region over a period of at least 20 years (for the RTP) and 4 years (for the FTIP). RTP and FTIP conformity uses travel demand and emission models to determine whether or not the implementation of those projects would conform to emission budgets or other tests at various analysis years showing that requirements of the FCAA and the SIP are met. If the conformity analysis is successful, the Metropolitan Planning Organization (MPO), Federal Highway Administration (FHWA), and Federal Transit Administration (FTA) make the determinations that the RTP and FTIP are in conformity with the SIP for achieving the goals of the FCAA. Otherwise, the projects in the RTP and/or FTIP must be modified until conformity is attained. If the design concept and scope and the “open- to-traffic” schedule of a proposed transportation project are the same as described in the RTP and FTIP, then the proposed project meets regional conformity requirements for purposes of project-level analysis.

Project-level conformity is achieved by demonstrating that the project comes from a conforming RTP and TIP; the project has a design concept and scope26 that has not changed significantly from those in the RTP and TIP; project analyses have used the latest planning assumptions and EPA-approved emissions models; and in PM areas, the project complies with any control measures in the SIP. Furthermore, additional

26 "Design concept" means the type of facility that is proposed, such as a freeway or arterial highway. "Design scope" refers to those aspects of the project that would clearly affect capacity and thus any regional emissions analysis, such as the number of lanes and the length of the project.

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analyses (known as hot-spot analyses) may be required for projects located in CO and PM nonattainment or maintenance areas to examine localized air quality impacts.

2.15.2 Affected Environment
The information in this section is based primarily on an Air Quality Report (November 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

The Napa County Airport includes an Automated Surface Observing System (ASOS) that provides hourly weather conditions such as wind speed, visibility, temperature, and precipitation that is maintained by the Federal Aviation Administration. This station is located approximately 5.6 miles south of the Project site and is representative of meteorological conditions near the Project. The climate of the Project area is generally Mediterranean-like in character, with short, cold, wet winters and warm, dry, and mostly clear summers. The Napa Valley is sandwiched between two mountain ranges: the Vaca to the east and the Mayacamas to the west. The valley’s proximity to the Pacific Ocean and San Francisco Bay has a significant influence on its climate. The prevailing winds in the Project area flow mainly from San Pablo Bay and the Petaluma Gap to the west and southwest. They help keep the valley fairly cool. Annual average rainfall is almost 20.4 inches (at the Napa County Airport), mainly falling during the winter months.

Existing Air Quality
The Bay Area Air District (Air District)27 monitors air quality conditions are over 30 locations throughout the Bay Area. The monitoring stations closest to the Project site are in Fairfield (approximately 12.5 miles southeast of the Project site) and in Vallejo (approximately 14 miles south of the Project site). However, the Fairfield site only monitors O3, while the Vallejo site monitors PM2.5, PM10, O3, CO, NOX (NO-NO2) and toxic organic compounds (TOCs). The Air District was also operating a monitoring site at the Napa Valley College campus from mid-2018 through 2021. The site was located approximately 1.8 miles south of the Project. Concentrations from this site are used to describe the ambient concentrations of criteria pollutants near the Project site prior to 2022.

Table 2.15-2 identifies the state and federal attainment status for regulated pollutants in the San Francisco Bay Area Air Basin. Under current designations of the Air Basin, the area is nonattainment for CAAQS for O3, PM10, and PM2.5 and Attainment for CO. For the NAAQS, the area is nonattainment for O3 and PM2.5, and Attainment for CO, PM10, NO2 and SO2.
27 The Bay Area Air District was formerly known as the Bay Area Air Quality Management District (BAAQMD) and was re-named on January 22, 2025.

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Table 2.15-2: State and Federal Attainment Status
Pollutant
State Attainment
Status Federal Attainment Status
Attainment Plan (O3, PM,
and CO)
O3
Nonattainment Nonattainment (Marginal –
2015 Standard)
Revised San Francisco Bay
Area Ozone Attainment
Plan for the 1-Hour
National Ozone Standard
(2001)
Respirable
PM (PM10) Nonattainment Unclassifiable/Attainment --
Fine PM
(PM2.5) Nonattainment Nonattainment (Moderate –
2006 Standard)
Bay Area Winter Emissions
Inventory for Primary PM2.5
& PM Precursors: Year
2010 (2012)
CO
Attainment Attainment
2004 Revision to the
California State
Implementation Plan for
Carbon Monoxide (2004)
NO2 Attainment Unclassifiable/Attainment --
SO2 Attainment Unclassifiable/Attainment --
Pb Attainment Unclassifiable/Attainment --
Visibility-
Reducing
Particles
Unclassified N/A --
Sulfates Attainment N/A --
Hydrogen
Sulfide Unclassified N/A --
Vinyl Chloride No Information
Available N/A --
The primary existing source of air pollution is vehicles traveling along the Project intersection and connecting local roadways. The Napa Valley Wine Train operates on a rail line approximately 1,000 feet from the western boundary of the Project. Engines used by the train are currently diesel powered but are planned to be replaced with ones that meet the EPA’s near-zero emissions standards (Tier 4). There are no permitted stationary sources of air pollution within 1,000 feet of the Project area.

Sensitive Receptors
The Air District defines sensitive receptors to include residential dwellings, schools, daycare centers, hospitals, and senior-care facilities. The zone of greatest concern for roadways is within 500 feet. Figure 2.15-1 shows the locations of sensitive receptors identified within 500 feet of the Project limits. Table 2.15-3 lists the type of sensitive receptors and the number identified within 500 feet of the Project’s footprint.

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Table 2.15-3: Sensitive Receptors Located within 500 Feet of the Project Limits Sensitive Receptor
Group
Number of
Receptors
Identified
Receptor Names Address
Distance
Between
Receptor and
Project (ft)
Schools/Preschools 1 The Oxbow School 530 3rd Street 248 Park 1 Neighborhood
Pocket Park
1100 Plaza
Avenue 500
Daycares 1 Children’s Cottage
Child Care
1078 East
Avenue 422
Residences 222+
Various single-family
and multi-family
buildings
Not applicable 40-500

2.15.3 Environmental Consequences
Clean Air Act Conformity
The Project is exempt from regional (40 CFR 93.127) conformity requirements.

However, a project-level conformity analysis for PM2.5 under 40 CFR 93.109 was required and obtained (see below). Separate listing of the project in the Regional Transportation Plan and Transportation Improvement Program, and their regional conformity analyses, is not necessary. The Project will not interfere with the timely implementation of Transportation Control Measures identified in the applicable SIP and regional conformity analysis.

The Project, however, is listed in the current RTP, Plan Bay Area 2050 (Project ID 21- T07-056). The RTP is financially constrained and have been determined to conform to the SIP (i.e., 2017 CAP). MTC’s financially constrained 2025 TIP also includes the Project (Project ID NAP170009) and has been found to conform to the SIP by FHWA and FTA as part of their approval of the Federal-Statewide TIP (FSTIP). The design concept and scope of the Project listed in the TIP and FSTIP are consistent with the project description in both the RTPs and the TIP.

Project-level conformity requires sponsors demonstrate their transportation project will not cause or contribute to any new localized CO, PM10, and/or PM2.5 violations, increase the frequency or severity of any existing CO, PM10, and/or PM2.5 violations, or delay timely attainment of any NAAQS or any required interim emission reductions or other SIP milestones. This is demonstrated through a hotspot analysis where Build and No- Build emissions are modeled, both with and without any mitigation measures committed to in the current RTP (i.e., Plan Bay Area 2050).

The Project is in an attainment area for CO and a nonattainment area for PM2.5.28 Thus, a project-level conformity analysis applies to the Project for PM2.5 under 40 CFR 93.109.

Hot-spot analysis for PM2.5 is only required for projects found to meet the definition of a Project of Air Quality Concern (POAQC) by the MTC’s Air Quality Conformity Task 28 Guidance from FHWA and Caltrans states that a project-level CO hot-spot analysis is not required to demonstrate project-level conformity in the area.

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Force (AQCTF). The Project was found not to be a POAQC by MTC’s AQCTF on March 27, 2025. Therefore, a PM2.5 hot-spot analysis is not required.

The PM2.5 project-level conformity determination by MTC was subject to public review as part of the Draft EIR/EA. Public comment was also requested regarding the project- level conformity analysis and determination. No comments were received on the air quality conformity determination. On May 18, 2026, the Project’s air quality conformity report was submitted to FHWA for their review and concurrence. In a letter to Caltrans dated June 4, 2026, FHWA concurred that the Five-Way Intersection Project conforms with the State Implementation Plan (SIP) in accordance with 40 CFR Part 93. A copy of the FHWA’s letter is contained in Appendix I.

Construction activities will not last for more than five years at one general location, so construction-related emissions do not need to be included in regional and project-level conformity analysis (40 CFR 93.123(c)(5)).

Criteria Air Pollutant Emissions
Air pollutant emissions associated with the roadways in the Project area were estimated for existing/baseline conditions to the forecasted conditions for the No-Build and Build Alternative given the Project’s opening year (2026), design year (2046), and RTP (Plan Bay Area 2050) horizon year (2050). The emissions for each scenario are summarized in Table 2.15-4. Operation of the Project would not involve other permanent sources of air pollutants, such as permitted stationary sources (e.g., diesel-powered emergency generators).

Table 2.15-4: Summary of Comparative Emissions Analysis Year Scenario/Analysis
CO
(lbs/day)
PM2.5
(lbs/day)
PM10
(lbs/day)
ROG
(lbs/day)
NOX
(lbs/day)
2023 Baseline (Existing Conditions) 2,686 68 363 169 413 2026 No-Build Alternative 2,486 75 402 192 365
2026 Build Alternative 2,486 75 402 192 365
2046 No-Build Alternative 1,855 84 469 160 178
2046 Build Alternative 1,855 84 469 160 178
2050 No-Build Alternative 1,897 87 486 162 180
2050 Build Alternative 1,897 87 486 162 180

ROG, NOX, and CO emissions will decrease in the future as older vehicles are replaced by newer vehicles with more stringent emissions and fuel economy standards. PM10 and PM2.5 emissions will increase in the future as a function of increases in fugitive emissions sources (i.e., road dust, break wear, tire wear), which is driven by increases

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in vehicle miles traveled (VMT). When compared to the No-Build Alternative, the Build Alternative would result in the same emissions because the proposed intersection improvements would not change regional travel patterns. Thus, the Build and No-Build Alternatives yield the same level of VMT and associated air pollutant emissions. It is possible that the Build Alternative could result in less emissions due to reduced vehicle delay (e.g., less idling) at the intersection, however, these reductions were not captured in the emission estimates shown in Table 2.15-4 because they are not included in the City’s travel demand model. Given that the Project would not result in an increase in operational criteria air pollutants, the Project would not exceed the Air District’s operational thresholds.

MSAT Emissions
Mobile source air toxics (MSATs) are emitted from highway vehicles and non-road equipment. Some toxic compounds are present in fuel and are emitted to the air when the fuel evaporates or passes through the engine unburned. Other toxics are emitted from the incomplete combustion of fuels or as by-products. Metal air toxics result from engine wear or from impurities in oil or gasoline. The US EPA has identified nine priority MSATs with significant contributions from mobile sources. These are 1,3-butadiene, acetaldehyde, acrolein, benzene, diesel particulate matter (DPM), ethylbenzene, formaldehyde, naphthalene, and polycyclic organic matter (POM).

According to the FHWA’s Interim Guidance this project is classified as a category 2 project (Projects with Low Potential MSAT Effects) because it would not change the traffic mix or create or significantly alter major roadways in the area. Similar to the process used for calculating criteria pollutant emissions, above, emissions of MSATs were calculated using the CT-EMFAC2021 model for baseline, No-Build, and Build Alternatives for all analysis years. The results are depicted in Table 2.15-5.

MSAT emissions for both the No-Build and Build Alternatives would be on average 37 percent lower than the baseline emissions, due in large part to vehicle fleet turnover that would result from the EPA’s national control programs. Nationally, these programs are projected to reduce annual MSAT emissions by over 76 percent between 2020 and 2060. Local conditions may differ from these national projections in terms of fleet mix and turnover, VMT growth rates, and local control measures. However, the magnitude of the U.S. EPA-projected reductions is so great (even after accounting for VMT associated with planned growth) that MSAT emissions in the study area are likely to be lower in the future for both the No-Build and Build alternatives.

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Table 2.15-5: Summary of Comparative MSAT Emissions Analysis (lbs/day) Year Scenario
1,3-butadiene
Acetaldehyde
Acrolein
benzene
DPM
ethylbenzene
formaldehyde
naphthalene
POM
2023 Baseline 0.27 1.22 0.024 4.60 2.44 1.92 2.79 0.26 0.073 2026 No-Build 0.24 1.13 0.022 4.59 2.37 2.06 2.57 0.22 0.066 2026 Build 0.24 1.13 0.022 4.59 2.37 2.06 2.57 0.22 0.066 2046 No-Build 0.12 0.45 0.013 3.13 0.99 1.61 1.05 0.10 0.028 2046 Build 0.12 0.45 0.013 3.13 0.99 1.61 1.05 0.10 0.028 2050 No-Build 0.12 0.41 0.012 3.15 0.92 1.63 0.98 0.10 0.025 2050 Build 0.12 0.41 0.012 3.15 0.92 1.63 0.98 0.10 0.025 Construction Air Quality Effects
Site preparation and construction would involve excavation, removing and improving existing roadways, paving new roadway surfaces, and installing new traffic control (i.e., signage and pavement markings). During construction, short-term degradation of air quality is expected from the release of particulate emissions (airborne dust) generated by excavation, grading, hauling, and other activities related to construction. Emissions from construction equipment and on-road vehicles powered by gasoline and diesel engines are also anticipated and would include CO, NOX, ROG, directly emitted PM10 and PM2.5, and toxic air contaminants (TACs) such as diesel exhaust particulate matter.

Construction activities in the area may temporarily increase traffic congestion and slow the speed of traffic, resulting in a temporary increase in on-road emissions. These emissions would be limited to the immediate area impacted by construction-related traffic.

Construction emissions were estimated using the latest version of Caltrans’ Cal- CET2021 emissions model which uses emission factors from EMFAC2021. The project’s estimated uncontrolled construction-related emissions are summarized in Table 2.15-6. The emissions are shown per project phase in pounds per day (lbs./day) and in total tons for the entire construction period. The CO2 equivalent (CO2e) emissions are represented in metric tons (MT) per phase. Average workday emissions are based on an assumption of 396 workdays.

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Table 2.15-6: Uncontrolled Construction Emissions
Phase/Activity ROG
(lbs/day)
CO
(lbs/day)
NOX
(lbs/day)
PM10
(lbs/day)
PM2.5
(lbs/day)
CO2e
(MT/phase)
Roadway Excavation &
Removal 5.0 14.1 24.1 1.7 1.5 362
Base/Subbase/Imported
Borrow 6.3 17.4 29.8 2.4 1.9 141
Paving 6.9 43.0 36.6 3.3 3.1 152
Drainage/Environment/
Landscaping 0.4 2.3 2.1 0.2 0.2 3
Traffic Signalization/
Signage/Striping/Painting 4.1 24.7 25.6 1.6 1.5 843
Average Workday Emissions*
(lbs/day)

5.1 lbs/day

20.7 lbs/day

25.8 lbs/day

2.0 lbs/day

1.5 lbs/day
1,001
MT/year
Total Construction
(tons or MT) 1.0 tons 4.1 tons 5.1 tons 0.4 tons 0.3 tons 1,501 MT Notes: * Based on 396 workdays
In addition to equipment exhaust emissions, construction activities would also temporarily generate fugitive dust in the form of PM10 and PM2.5 particularly during site preparation and grading. Sources of fugitive dust would include disturbed soil at the construction site and trucks carrying uncovered loads of soil. Unless properly controlled, vehicles leaving the site would deposit mud on local streets, which could be an additional source of airborne dust after it dries. Caltrans’ Standard Specifications will reduce air quality impacts resulting from construction activities consistent with the Air District’s BMPs for construction period emissions.

Asbestos and Lead
Naturally occurring asbestos (NOA) in California may occur in serpentinite and ultramafic rocks. NOA is commonly found in the foothill region of the Sierra Nevada, the Coast Ranges, and northwestern California. In an NOA area, construction could disturb the NOA, and it may become airborne. Therefore, a review of the Project footprint and of asbestos areas in California was completed to determine if NOA would be present in the area. Based on the information on NOA provided by the California Air Resources Board (CARB), there are no NOA areas located within the project limits and further analysis is not needed. As previously discussed in Section 2.14 Hazardous Waste/ Materials, the existing residential building could contain ACMs that could be released during demolition. The Project would implement AMMs to ensure that demolition materials are properly handled and disposed of to protect construction workers’ health (see Section 2.14 Hazardous Waste/Materials).

Similarly, ADL and LBP may also be present in the existing roadway materials and the existing residence at 801 Silverado Trail. The Project would implement AMMs to ensure that demolition materials potentially containing lead are properly handled and disposed

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of to protect construction workers’ health (see Section 2.14 Hazardous Waste/ Materials).

No-Build Alternative
The No-Build Alternative would not result in an increase in short-term emissions.

However, as vehicle congestion and delay worsens at the Project intersection, the No- Build Alternative could result in greater long-term emissions than the Build Alternative.

2.15.4 Climate Change
Neither the United States Environmental Protection Agency (U.S. EPA) nor the Federal Highway Administration (FHWA) has issued explicit guidance or methods to conduct project-level greenhouse gas analysis. FHWA emphasizes concepts of resilience and sustainability in highway planning, project development, design, operations, and maintenance. Because there have been requirements set forth in California legislation and executive orders on climate change, the issue is addressed in the California Environmental Quality Act (CEQA) chapter of this document. The CEQA analysis may be used to inform the National Environmental Policy Act (NEPA) determination for the project.

2.15.5 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, or mitigation measures are required for the Project operational period. The following measures will be implemented in accordance with Caltrans’ Standard Specifications in Section 14.9 Air Quality (2023) and Section 13 Water Pollution Control (2023) for the purpose of avoiding and minimizing the construction-related air quality effects of the Project that pertain to equipment exhaust.

AMM AIR-1.1: Caltrans or the general contractor for the project shall submit a list of all off-road equipment greater than 25 horsepower (hp) that would be operated for more than 20 hours over the entire duration of project construction, including equipment from subcontractors to the relevant air district for review and certification. The list shall include all information necessary to ensure the equipment meets the following requirements:
• Equipment shall be zero emissions or have engines that meet or exceed either EPA or CARB Tier 4 off-road emission standards, or it shall have engines that are retrofitted with a CARB Level 3 Verified Diesel Emissions Control Strategy (VDECS), if one is available for the equipment being used. Equipment with engines that meet Tier 4 Interim or Tier 4 Final emission standards automatically meet this requirement; therefore, a VDECS would not be required.
• Idling time of diesel-powered construction equipment and trucks shall be limited to no more than two minutes. Clear signage of this

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idling restriction shall be provided for construction workers at all access points.

AMM AIR-1.2: Portable diesel generators shall be prohibited. Grid power electricity should be used to provide power at construction sites; or propane and natural gas generators may be used when grid power electricity is not feasible.

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2.16 Noise and Vibration

2.16.1 Introduction
Noise is measured in "decibels" (dB), which is a numerical expression of sound levels on a logarithmic scale. A noise level that is 10 dB higher than another noise level has ten times as much sound energy and is perceived as being twice as loud. A sound change of less than three dB is just barely perceptible, and then only in the absence of other sounds. Intense sounds of 140 dB are so loud that they are painful and can cause damage with only brief exposure. These extremes are not commonplace in our normal working and living environments. An "A-weighted decibel" (dBA) approximates the frequency response of the average young ear when listening to most ordinary everyday sounds. Thus, traffic noise impact analyses commonly use the dBA.

Regarding traffic-generated noise, noise levels rise as vehicle speeds, overall volumes, and truck volumes increase. In general, a doubling of traffic results in a three dBA increase in noise at a nearby receptor, assuming a relatively homogeneous traffic composition (i.e., mainly passenger cars). The peak noise hour is typically not the peak commute hour due to lower operating speeds during the latter.

2.16.2 Regulatory Setting
The National Environmental Policy Act (NEPA) of 1969 and the California Environmental Quality Act (CEQA) provide the broad basis for analyzing and abating highway traffic noise effects. The intent of these laws is to promote the general welfare and to foster a healthy environment. The requirements for noise analysis and consideration of noise abatement and/or mitigation, however, differ between NEPA and CEQA.

California Environmental Quality Act
CEQA requires a strictly baseline versus build analysis to assess whether a proposed project will have a noise impact. If a proposed project is determined to have a significant noise impact under CEQA, then CEQA dictates that mitigation measures must be incorporated into the project unless those measures are not feasible. The rest of this section will focus on the NEPA/Title 23 Part 772 of the Code of Federal Regulations (23 CFR 772) noise analysis; please see Chapter 3 of this document for further information on noise analysis under CEQA.

National Environmental Policy Act and 23 CFR 772
For highway transportation projects with Federal Highway Administration (FHWA) involvement (and Caltrans, as assigned), the Federal-Aid Highway Act of 1970 and its implementing regulations (23 CFR 772) govern the analysis and abatement of traffic noise impacts. The regulations require that potential noise impacts in areas of frequent human use be identified during the planning and design of a highway project. The regulations include noise abatement criteria (NAC) that are used to determine when a noise impact would occur. The NAC differ depending on the type of land use under analysis. For example, the NAC for residences (67 dBA) is lower than the NAC for

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commercial areas (72 dBA). The following table lists the noise abatement criteria for use in the NEPA/23 CFR 772 analysis.

Table 2.16-1: Noise Abatement Criteria
Activity
Category
NAC, Hourly A-
Weighted Noise Level,
Leq(h) Description of activity category
A 57 (Exterior) Lands on which serenity and quiet are of extraordinary significance and serve an important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose.

B1 67 (Exterior) Residential.

C1 67 (Exterior) Active sport areas, amphitheaters, auditoriums, campgrounds, cemeteries, day care centers, hospitals, libraries, medical facilities, parks, picnic areas, places of worship, playgrounds, public meeting rooms, public or nonprofit institutional structures, radio studios, recording studios, recreation areas, Section 4(f) sites, schools, television studios, trails, and trail crossings.

D 52 (Interior) Auditoriums, day care centers, hospitals, libraries, medical facilities, places of worship, public meeting rooms, public or nonprofit institutional structures, radio studios, recording studios, schools, and television studios.

E 72 (Exterior) Hotels, motels, offices, restaurants/bars, and other developed lands, properties, or activities not included in A–D or F.

F No NAC—reporting
only
Agriculture, airports, bus yards, emergency services, industrial, logging, maintenance facilities, manufacturing, mining, rail yards, retail facilities, shipyards, utilities (water resources, water treatment, electrical, etc.), and warehousing.

G No NAC—reporting
only
Undeveloped lands that are not permitted.
1 Includes undeveloped lands permitted for this activity category.

Figure 2.16-1 lists the noise levels of common activities to enable readers to compare the actual and predicted highway noise levels discussed in this section with common activities.

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Figure 2.16-1: Noise Levels of Common Activities

According to Caltrans’ Traffic Noise Analysis Protocol for New Highway Construction and Reconstruction Projects, April 2020, a noise impact occurs when the predicted future noise level with the project substantially exceeds the existing noise level (defined as a 12 dBA or more) or when the future noise level with the project approaches or exceeds the NAC. A noise level is considered to approach the NAC if it is within 1 dBA of the NAC.

If it is determined that the project will have noise impacts, then potential abatement measures must be considered. Noise abatement measures that are determined to be reasonable and feasible at the time of final design are incorporated into the project plans and specifications. This document discusses noise abatement measures that may be incorporated in the project.

Caltrans’ Traffic Noise Analysis Protocol sets forth the criteria for determining when an abatement measure is reasonable and feasible. Feasibility of noise abatement is basically an engineering concern. Noise abatement must be predicted to reduce noise

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by at least 5 dB at an impacted receptor to be considered feasible from an acoustical perspective. It must also be possible to design and construct the noise abatement measure for it to be considered feasible. Factors that affect the design and constructability of noise abatement include, but are not limited to, safety, barrier height, topography, drainage, access requirements for driveways, presence of local cross streets, underground utilities, other noise sources in the area, and maintenance of the abatement measure. The overall reasonableness of noise abatement is determined by the following three factors: 1) the noise reduction design goal of 7 dB at one or more impacted receptors; 2) the cost of noise abatement; and 3) the viewpoints of benefited receptors (including property owners and residents of the benefited receptors).

2.16.3 Affected Environment
The information in this section is based primarily on a Noise Study Report (December 2024), a Construction Vibration Report (April 2025), and a Noise Abatement Decision Report (April 2025) that were prepared for the Project. These studies are incorporated into this Final EIR/EA by reference. Copies of these studies are available for review at the locations listed inside the front cover of this document.

A noise monitoring survey of the Project area was conducted from August 5, 2024, to August 7, 2024. The noise monitoring survey included eight short-term (ten minute intervals) measurements and two long-term measurements (48 hours) taken at the locations shown in Figure 2.16-2 and Figure 2.16-3. Noise levels are summarized in Table 2.16-2 and Table 2.16-3. The primary noise source in the Project area is vehicle traffic from the local roadways. Land uses in the Project area consist of Category B receptors (i.e., residences), Category C (i.e. cemeteries), Category D (i.e. schools, daycare centers), and Category E (i.e. restaurants, retail).

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Table 2.16-2: Summary of Short-Term Noise Measurements
Receptor ID Location Land Use Start Time
8/6/24
10-minute Leq
(dBA)
ST-1 1021 Evans Avenue Residential 9:20am
9:30am
67 67
ST-2 1008 Silverado Trail Residential 9:20am
9:30am
62 61
ST-3 1010 East Avenue Residential 9:50am
10:00am
66 65
ST-4 801 Silverado Trail Residential 10:30am
10:40am
66 65
ST-5 420 3rd Street Residential 10:30am
10:40am
64 63
ST-6 Tulocay Cemetery – 411
Coombsville Road Cemetery 9:50am
10:00am
64 65
ST-7 36 Coombsville Road Residential 11:00am
11:10am
67 67
ST-8 620 Silverado Trail Residential 11:00am
11:10am
71 72

Table 2.16-3: Summary of Long-Term Noise Monitoring
Receptor ID Location Date Loudest Hour(s) Loudest Hour
Leq[h], dBA
LT-1 300 Taylor Street
8/5/24
8/6/24
8/7/24
1:00pm
7:00am
7:00am
71 71
71 LT-2 Across from 670
Silverado Trail
8/5/24
8/6/24
8/7/24
1:00pm
10:00am
7:00am
73 73
71 2.16.4 Environmental Consequences
Long-Term Operational Noise Impacts
The Project is a Type I project as it would physically alter an existing highway (SR 121) and significantly change its alignment by replacing the existing intersection with two roundabouts. Therefore, the Project requires noise abatement to be considered for impacted receptors. Compliance with 23 CFR 772 provides compliance with the noise impact assessment requirements of NEPA.

The primary source of noise from Project operation would be traffic using the proposed roundabouts. The Project does not propose any other noise-generating uses. The 31 modeled receptor locations, shown in Figure 2.16-4 through Figure 2.16-8, were used to calculate existing and future traffic noise levels. Future noise level conditions were calculated for the project design year, 2046. A summary of the existing and future noise levels at the identified receptor locations is given in Table 2.16-4.

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Table 2.16-4: Predicted Future Noise Levels
Receptor ID, Address Land Use
Existing
Noise Level,
Leq [h], dBA
2046 No-Build
Alt. Noise
Levels, Leq [h],
dBA
2046 Build Alt.

Noise Levels,
Leq [h], dBA
R1, 1114 Silverado Trail Residential 62 63 63
R2, 1041 Evans Avenue Residential 60 61 61
R3, 1072 Raymond Avenue Residential 58 60 60
R4, 1034 Evans Avenue Residential 59 60 60
R5, 1017 East Avenue Residential 60 61 62
R6, 1078 East Avenue School 47 49 49
R7, 1054 East Avenue Residential 61 63 63
R8, 1018 East Avenue Residential 61 63 63
R9, 1010 East Avenue Residential 62 64 65
R10, 891 Silverado Trail Restaurant 67 68 71
R11, 802 Juarez Street Residential 59 60 61
R12, 432 3rd Street Residential 47 48 50
R13, 530 3rd Street School 49 50 50
R14, 530 3rd Street School 45 47 47
R15, 619 3rd Street Residential 47 48 48
R16, 724 Bailey Street Residential 53 55 55
R17, 427 3rd Street Residential 53 55 55
R18, 36 Coombsville Road Residential 57 58 59
R19, 110 Coombsville Road Residential 54 55 55
R20, 81 Hoffman Avenue Residential 61 62 62
R21, 411 Coombsville Road Cemetery 53 54 54
R22, 81 Davis Avenue Residential 55 57 57
R23, 640 Silverado Trail Residential 56 57 57
R24, 610 Silverado Trail Residential 51 52 52
R25, 606 CA-21 Residential 56 58 58
R26, 608 Silverado Trail Recreation
Area 56 58 58
R27, 1078 East Avenue Day Care
Center 56 58 58
R28, 530 3rd Street School 65 66 66
R29, 1010 East Avenue Residential 61 63 64
R30, 1021 Evans Avenue Residential 63 64 64
R31, 1008 Silverado Trail Residential 56 58 59

As shown in Table 2.16-4, noise levels would increase by up to two dBA over existing conditions under 2046 No-Build conditions. When compared to No-Build conditions, increases in noise levels under 2046 Build conditions would range from zero to three dBA. The changes to noise levels that would result from the Project are not considered substantial as they would not be at or above the Caltrans 12 dBA threshold. For these reasons, Project operation would not result in a substantial increase in ambient noise

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levels in excess of established standards. However, the 2046 Build Alternative traffic noise levels are predicted to approach or exceed the NAC at one Category E receptor, R10.

Project noise levels will approach FHWA’s NAC at the outdoor patio area of the El Rancho Grande restaurant located at 891 Silverado Trail and represented by R10 in Figure 2.16-5. As a result, the feasibility and reasonableness allowances for noise abatement measures were considered. Noise barriers are the only form of noise abatement considered for this Project.

The feasibility of constructing a new soundwall along the Project alignment from southbound SR 121 to westbound Third Street was determined by Caltrans’ required five dBA minimum reduction in noise level as well as the overall constructability. The reasonableness of the soundwall was determined using the following three factors contained in the Protocol:
• The noise reduction design goal (a barrier must be predicted to provide at least seven dB of noise reduction at one or more benefitted receptors). • The cost of noise abatement (reasonable allowance per benefitted receptor of $146,000)
• The viewpoints of benefitted receptors (including views of the restaurant from the roadway)
Evaluated Barrier 1, as shown in Figure 2.16-9, would feasibly abate traffic noise at the restaurant outdoor patio. The seven dB noise reduction goal would be met at a minimum height of eight feet. The line of sight between truck stacks and receptors would be broken at a minimum height of 12 feet.

Barrier 1 was determined to feasibly abate traffic noise by meeting the Protocol’s seven- dBA noise reduction goal at a minimum height of eight feet. As defined in Section 772.5 of the regulation, a reasonable allowance of the cost of noise abatement is set at $146,000 per benefited receptor. The overall reasonable allowance calculated for Barrier 1 is $146,000 as there is only a single benefitted receptor. The estimated construction cost for the barrier was calculated based on Caltrans’ unit cost database, assuming a barrier length of 140 feet. The reasonable allowance would not be exceeded by an eight foot soundwall achieving the minimum noise reduction goal at a length of 140 feet or by a 12 foot soundwall which would be tall enough to break the line of sight between trucks stacks and receptors at a length of 140 feet.

As the projected construction cost is less than the total reasonable allowance, Barrier 1, at a height of up to 12 feet, is financially feasible. As a negative secondary effect, Barrier 1 would obstruct the ability to see the El Rancho Grande restaurant from SR 121 northbound and southbound lanes. Furthermore, Barrier 1 would obstruct views all across the roadway along the southbound portion of SR 121 toward the northern roundabout. The construction of Barrier 1 would also require the acquisition of additional property from the parcel on which El Rancho Grande currently operates as the currently designed right-of-way is not wide enough to accommodate the evaluated barrier.

EXHIBIT A
EVALUATED BARRIER 1 LOCATION FIGURE 2.16-9

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Given the obstruction of views and additional right-of-way requirements the City conducted outreach to the property owner and tenant of the El Rancho Grande parcel regarding construction of a soundwall on their property. The Project currently does not propose a soundwall and the property owner and tenant requested no soundwall be constructed in comments to the City during circulation of the Draft EIR/EA.

Short-Term Noise Impacts During Construction
Project construction is anticipated to occur over a period of approximately 18 months.

Noise generated by Project-related construction activities would be a function of the noise levels generated by individual pieces of construction equipment, the type and amount of equipment operating at any given time, the timing and duration of construction activities, the proximity of nearby sensitive land uses, and the presence or lack of shielding at these sensitive land uses. Construction noise levels would vary on a day-to-day basis during each phase of construction, depending on the specific task being completed.

Table 2.16-5 presents construction noise levels calculated for each major phase of construction at a distance of 50 feet, based on calculations conducted in FHWA’s Roadway Construction Noise Model using project-specific construction information. In some instances, maximum instantaneous noise levels are calculated to be slightly lower than hourly average noise levels. This occurs because the model reports the maximum instantaneous noise level generated by the loudest single piece of construction equipment, while reporting the hourly average noise levels resulting from the additive effect of multiple pieces of construction equipment operating simultaneously. Noise generated by construction equipment drops off at a rate of six dB per doubling of distance.

Table 2.16-5: Construction Noise Levels at 50 Feet

Construction Phase Maximum Noise Level
(Lmax, dBA)
Hourly Average Noise
Level (Leq[h], dBA)
Roadway Excavation & Removal 90 91
Base/Subbase/Imported Borrow 90 91
Paving 90 91
Drainage/Environmental/Landscaping 90 90
Traffic Signalization Signage 90 90
As shown in Table 2.16-5, most construction phases would generate average noise levels that would exceed ambient daytime noise levels at adjacent land uses by approximately 15 to 20 dBA Leq[h]. Construction noise levels would not be expected to exceed the quantitative noise limits established by Caltrans of 86 dBA Lmax at 50 feet from job site activities from 9:00 p.m to 6:00 a.m. The Project would be subject to Section 14-8.02, Noise Control of the latest Caltrans Standard Specification and shall implement noise control measures as required by the City of Napa Municipal Code Section 8.08.025.

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Vibration Impacts
Traffic, including heavy trucks traveling on a highway, rarely generates vibration amplitudes high enough to cause structural or cosmetic damage. Therefore, the Project would not result in generation of excessive vibration during operation. Demolition and construction activities required for construction often generate perceptible vibration levels and levels that could affect nearby structures when heavy equipment or impact tools (e.g., jackhammers, hoe rams) are used in the vicinity of nearby sensitive land uses. The Project would not require pile-driving, which can cause excessive vibration.

Construction activities with the greatest potential of generating perceptible vibration levels would include the removal of pavement and soil, the dropping of heavy objects, and the movement of heavy tracked equipment. Table 2.16-6 presents typical vibration levels that could be expected from representative construction equipment at a reference distance of 25 feet and calculated vibration levels at distances of 50 feet and 100 feet.

Vibration levels are highest close to the source and attenuate with increasing distance depending on soil conditions.

Table 2.16-6: Vibration Source Levels of Construction Equipment Equipment PPV at 25 ft (in/sec) PPV at 50 ft (in/sec) PPV at 100 ft (in/sec) Clam shovel drop 0.202 0.094 0.044
Hydromill (slurry wall)
in soil 0.022 0.004 0.002
Hydromill (slurry wall)
in rock 0.047 0.008 0.004
Vibratory Roller 0.210 0.098 0.046
Hoe Ram 0.089 0.042 0.019
Large bulldozer 0.089 0.042 0.019
Caisson drilling 0.089 0.042 0.019
Loaded trucks 0.076 0.035 0.017
Jackhammer 0.035 0.016 0.008
Small bulldozer 0.003 0.001 0.001

Caltrans identifies a vibration limit of 0.5 in/sec PPV as the threshold at which there is a potential risk of damage to new residential and modern commercial/industrial structures,

0.3 in/sec PPV for older residential structures, and a conservative limit of 0.25 in/sec PPV for historic and some old buildings. Distances to exceedances of the vibration limits for various structure types are shown in Table 2.16-7.

Table 2.16-7: Distance to Exceedance of Vibration Limit by Structure Type Structure Type
Threshold
(in/sec
PPV)
Caisson
Drilling
Vibratory
Roller
Hoe Ram,
Large
bulldozer
Loaded
trucks Jackhammer
Historic Building 0.25 10 ft 22 ft 10 ft 9 ft 5 ft

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Structure Type
Threshold
(in/sec
PPV)
Caisson
Drilling
Vibratory
Roller
Hoe Ram,
Large
bulldozer
Loaded
trucks Jackhammer
Older Residences 0.3 9 ft 18 ft 9 ft 8 ft 4 ft
New Residential and
Commercial/Industrial
Buildings

0.5 6 ft 12 ft 6 ft 5 ft 3 ft

Based on a review of the City of Napa’s historic resource inventories/mapping, for the purpose of vibration analysis, there are 23 historical structures located within 500 feet of the Project vicinity, as shown Figure 2.16-10. Of these identified structures, only eight are located within 200 feet of the Project limits. Vibration levels were calculated for each of these eight structures assuming each piece of equipment would operate along the nearest Project boundary closest to each historical building. An additional historic building at 801 Silverado Trail is located within the project limits, however, it would be demolished as part of the Project and therefore, would not be affected by construction vibration.

Vibration levels generated by vibratory rollers and the dropping of heavy objects would exceed the 0.25 in/sec PPV and 0.3 in/sec PPV thresholds at the following historical buildings and older residences, respectively, shown in Figure 2.16-11. • 406 3rd Street (historical building)
• 1031 Evans Avenue (historical building)
• Garage at 802 Juarez Street (older residence)
• 5 Hennessey Drive (older residence)
• 607 Silverado Trail (older residence)
• Barn at 1017 East Avenue (older residence)
• 36 Coombsville Road (older residence)
Additionally, vibration levels generated by vibratory rollers, hoe rams, large bulldozers, caisson drilling, and the dropping of heavy objects would exceed the 0.5 in/sec PPV threshold at the following commercial buildings shown in Figure 2.16-12. • El Rancho Grande at 891 Silverado Trail
• Posh Motors at 800 Silverado Trail
• Napa Tires & Wheels at 713 Silverado Trail

EXHIBIT A
Hennessey DriveHennessey DriveDavis Avenue
Linell Avenue Hoﬀman Avenu
Avenu
e
Coombsville Road
Tulocay Drive
Redwood Drive
East Avenue
Evans Avenue
Ramona Avenue
Bonita Avenue
Julian Avenue
Montecito Boulevard
Raymond Avenue
Silverado Trail
Silverado Trail
Post Street
2nd Street
Juarez Street
Taylor Street
3rd Street
1st Street
Bailey Street
4th Street Burnell Street
Soscol Avenue
Napa River
Napa River
U.P.R.R.

U.P.R.R.

Davis Avenue
Linell Avenue Hoﬀman e
Coombsville Road
Tulocay Drive
Redwo
od Drive
East Avenue
Evans Avenue
Ramona Avenue
Bonita Avenue
Julian Avenue
Montecito Boulevard
Raymond Avenue
Silverado Trail
Silverado Trail
Post Street
2nd Street
Juarez Street
Taylor Street
3rd Street
1st Street
Bailey Street
4th Street Burnell Street
Soscol Avenue
Napa River
Napa River
U.P.R.R.

U.P.R.R.

Photo Date: Jun. 2023
0 50 300 400 600 Feet
Project Boundary
Staging Area
Historical Building
Aerial Source: Google Earth Pro, Jul. 19, 2024.

IDENTIFIED HISTORICAL BUILDINGS IN THE PROJECT AREA FIGURE 2.16-10

EXHIBIT A

EXHIBIT A
Hennessey DriveHennessey DriveDavis Avenue
Linell Avenue Hoﬀman Avenue
venue
Coombsville Road
Tulocay Drive
Redwood Drive
East Avenue
Evans Avenue
Ramona Avenue
Bonita Avenue
Julian Avenue
Montecito Boulevard
Raymond Avenue
Silverado Trail
Silverado Trail
Post Street
2nd Street
Juarez Street
Taylor Street
3rd Street
1st Street
Bailey Street
4th Street Burnell Street
Soscol Avenue
Napa River
Napa River
U.P.R.R.

U.P.R.R.

Davis Avenue
Linell Avenue Hoﬀman A
Coombsville Road
Tulocay Drive
Redwo
od Drive
East Avenue
Evans Avenue
Ramona Avenue
Bonita Avenue
Julian Avenue
Montecito Boulevard
Raymond Avenue
Silverado Trail
Silverado Trail
Post Street
2nd Street
Juarez Street
Taylor Street
3rd Street
1st Street
Bailey Street
4th Street Burnell Street
Soscol Avenue
Napa River
Napa River
U.P.R.R.

U.P.R.R.

Photo Date: Jun. 2023
0 50 300 400 600 Feet
Project Boundary
Staging Area
Commercial Building
Aerial Source: Google Earth Pro, Jul. 19, 2024.

IDENTIFIED COMMERCIAL BUILDINGS WITHIN 15 FEET OF THE PROJECT LIMITS FIGURE 2.16-12

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No-Build Alternative
The No-Build Alternative would not result in any changes to the existing ambient noise environment and would not introduce any new vibration sources.

2.16.5 Avoidance, Minimization, and/or Abatement Measures This section describes the avoidance, minimization, and mitigation measures that were evaluated for inclusion in the Project.

Measures for Short-Term Construction Noise Impacts
For the purpose of minimizing and avoiding short-term construction noise impacts, the following measures will be implemented by the Project:

AMM NOI-1.1: All construction equipment shall conform to Section 14-8.02, Noise Control, of the latest Standard Specifications.

AMM NOI-1.2: When feasible, noise-generating construction activities shall be restricted to between 7:00 a.m. and 7:00 p.m. on weekdays, with no construction occurring on weekends or holidays. If work is necessary outside of these hours, Caltrans shall require the contractor to implement a construction noise monitoring program and provide additional noise controls where practical and feasible.

AMM NOI-1.3: Noise generating equipment shall be located as far as practical from sensitive receptors when sensitive receptors adjoin or are near the construction Project area.

AMM NOI-1.4: "Quiet" air compressors and other "quiet" equipment shall be utilized where such technology exists.

Measures for Short-Term Construction Vibration Impacts
The following measures shall be implemented for the purpose of avoiding, minimizing, and mitigating short-term vibration effects that would occur during Project construction.

MM NOI-2.1: Avoid the use of vibratory rollers within 25 feet of structures. Static mode compaction shall be used when construction activities are less than 25 feet from structures.

MM NOI-2.2: Avoid dropping heavy objects or equipment within 25 feet of structures.

MM NOI-2.3: Avoid the use of hoe rams, large bulldozers, and caisson drilling equipment within 15 feet of structures. If vibratory rollers must be used within 25 feet and all other equipment must be used within 15 feet of structures, the following measures will be required:
• Contractor must perform vibration monitoring, crack monitoring and photo/video documentation of the effected facilities during construction. The requirements to perform vibration monitoring,

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crack monitoring and photo/video documentation will be included in the Project's construction specifications as part of the construction contract documents.

EXHIBIT A

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2.17 Energy

2.17.1 Regulatory Setting
The National Environmental Policy Act (NEPA) (42 United States Code [USC] Part 4332) requires the identification of all potentially significant impacts to the environment, including energy impacts.

The California Environmental Quality Act (CEQA) Guidelines section 15126.2(b) and Appendix F, Energy Conservation, require an analysis of a project’s energy use to determine if the project may result in significant environmental effects due to wasteful, inefficient, or unnecessary use of energy, or wasteful use of energy resources.

2.17.2 Affected Environment
The information in this section is based primarily on a Energy Analysis Report (September 2024) that was prepared for the Project. This study is incorporated into this Draft EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

Within the Project limits, energy is primarily consumed in the form of gasoline used for vehicle travel. Vehicle traffic in the area is generated primarily by the many residential, commercial, and civic developments near or within the Project area. Average vehicle miles traveled (VMT) within the City is 1,285,389 miles per day. Trucks, defined as light duty trucks, medium-heavy duty trucks, and heavy-heavy duty trucks are estimated to be 3.9 percent of the vehicle fleet, while all other vehicles (i.e., non-trucks) are estimated to be 96.1 percent.

A poor driving surface can contribute to an increase in fuel consumption. The Pavement Condition Index (PCI)29 for the segment of SR-121 northbound and southbound impacted by the Project is considered “Good/Excellent” with a rating of between 80 and 100. East Avenue has a PCI of between 80 and 100 (Excellent/Very Good), while Third Street and Coombsville Road have a PCI between 60 and 79 (Good/Fair). Thus, the pavement in the Project area is considered in good condition and does not require immediate attention as the ride quality is good to excellent.

Transportation System Management (TSM) strategies located along the corridor include automobile, transit, ridesharing programs, and bicycle and pedestrian elements (i.e., sidewalks). Other sources of energy consumption within the Project limits include electricity used to power streetlights and traffic signals.

29 PCI is a measure of the number and severity of pavement distresses observed during a visual inspection of the roadway expressed as an index from 0 (failed condition) to 100 (excellent or new condition).

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2.17.3 Environmental Consequences
Short-Term Construction Impacts
Construction is estimated to last for approximately 18 months. Fuel and energy consumption would be required to operate equipment and power vehicles to, from, and on the site. Construction activities in the area may temporarily increase traffic congestion and slow the speed of traffic, resulting in a temporary increase in fuel consumption. Such an increase would be limited to the immediate area impacted by construction-related traffic.

Fuel and energy consumption that would be consumed during construction of the Project was estimated using Cal-CET2021. The results of the modeling are summarized in Table 2.17-1.

Table 2.17-1: Build Alternative Construction Energy Consumption Construction Type Fuel/Energy
Source
Annual Average
Consumption
Total
Consumption
Total Fuel
Consumption
Gasoline (gallons) 20,995 41,990
Diesel (gallons) 48,790 97,580
Electricity (kWh) 10,520 21,039
Total Energy
Consumption
(MBTU)
Gasoline 2,524 5,048
Diesel 6,703 13,406
Electricity 36 72
Total 9,263 18,526

The overall construction schedule and process for the Project is already designed to be efficient in order to avoid excess monetary costs. That is, equipment and fuel are not typically used wastefully on the site because of the added expense associated with renting the equipment, maintaining it, and fueling it. Therefore, the opportunities for efficiency gains during construction are limited. However, incorporation of AMM AIR-1.1 and 1.2 would minimize energy consumption from construction activities.

Additionally, the Project would also be required to comply with the City’s Construction and Demolition Debris Recycling Ordinance. As such, 100 percent of identified materials would be source-separated on-site and recycled. Additionally, because the project would exceed 5,000 square feet, it must achieve an overall salvage or recycle rate of 50 percent of all project debris generated. A Waste Reduction and Recycling Plan (WRRP) must be submitted and approved before a building or demolition permit can be issued, and the contractor must demonstrate compliance with the City’s requirements at the end of the project by submitting corresponding documentation such as weight tags from appropriate facilities.

For these reasons, the short-term energy used during construction would not be significantly wasteful, inefficient, or unnecessary.

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Long-Term Operation Impacts
It is anticipated that traffic will continue to increase at the Project intersection based on population growth forecasts used to develop the City’s travel demand model. Increased traffic would result in a corresponding increase in fuel consumption. However, given that the Project would not increase vehicle capacity at the Project intersection or the local roadways, the Build Alternative would not result in an increase in fuel consumption compared to the No Build Alternative. Additionally, the Project would provide a new shared-use path and sidewalks through the proposed roundabouts, which could further reduce VMT and fuel consumption. For these reasons, the Project would not result in wasteful, inefficient, or unnecessary consumption of energy or wasteful use of energy resources. The Project would not obstruct or conflict with the RTP (Plan Bay Area 2050) or other plans for renewable energy or energy efficiency.

Indirect Energy Impacts
Indirect energy usage is primarily associated with project maintenance, i.e., fuel used by equipment for periodic maintenance of the system. Many other sources contribute indirectly to the energy consumption of a transportation system, but they can be difficult to reliably quantify at the project level. Maintenance and landscaping activities are anticipated to be minimal and are necessary in order to maintain the integrity of the system. Therefore, the Project is not anticipated to result in wasteful, inefficient, or unnecessary indirect consumption of energy resources.

No-Build Alternative
The No-Build Alternative would not result in any increase in short-term energy consumption. However, as vehicle delay and congestion increase at the Project intersection, vehicles would idle longer and consume more gasoline over the long-term.

2.17.4 Avoidance, Minimization, and/or Mitigation Measures No avoidance, minimization, and/or mitigation measures are required.

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BIOLOGICAL ENVIRONMENT

2.18 Natural Communities
This section of the document discusses natural communities of concern. The focus of this section is on biological communities, not individual plant or animal species. This section also includes information on wildlife corridors and habitat fragmentation. Wildlife corridors are areas of habitat used by wildlife for seasonal or daily migration. Habitat fragmentation involves the potential for dividing sensitive habitat and thereby lessening its biological value.

Habitat areas that have been designated as critical habitat under the Federal Endangered Species Act are discussed below in Section 2.20 Threatened and Endangered Species.

2.18.1 Affected Environment
The information in this section is based primarily on a Natural Environment Study (Minimal Impacts) (NES[MI]) (August 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference. A copy of this study is available for review at the locations listed inside the front cover of this document.

To assess the existing biological conditions of the Project site, Sequoia Ecological Consultants conducted a desktop review of available literature and performed a biological survey on March 7, 2024. The Project area primarily consists of paved and gravel surfaces surrounded by residential and commercial development. The roadway is bordered with heavily disturbed shoulders, which include primarily ornamental plants with some sparse non-native annual grassland. One roadside drainage in the Project vicinity runs along the southern end of Silverado Trail and feeds into a culvert; however, this feature does not occur within the Project footprint and will not be impacted. No designated critical habitat exists within or adjacent to the Project limits.

The Napa River is a 55 mile long river that runs from Mount Saint Helena to the San Pablo Bay. Salinity within the river varies from saline and brackish at the bay to freshwater upstream and within the vicinity of the Project site. The river provides riparian habitat which serves as a habitat and wildlife corridor for many terrestrial species. The Napa River is approximately 275 feet from the Project construction limits and separated by the Oxbow School on Third Street, with the exception of the staging area on Third Street where a 200-foot stretch of the Napa River runs parallel to the northern boundary of the staging area. Within the staging area, the ground is paved and vegetation is landscaped. A narrow strip of riparian vegetation on a steep riverbank grows between the staging area and the Napa River.

2.18.2 Environmental Consequences
As previously discussed, there is riparian habitat along the northern boundary of the proposed staging area. There are no other sensitive habitats or communities within the Project limits. The Project would not result in any direct impacts to riparian habitat.

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However, the Project could result in indirect impacts to the riparian habitat adjacent to the proposed staging area if construction fluids are spilled or equipment otherwise disturbs the adjacent habitat.

No-Build Alternative
The No-Build Alternative would not affect any natural communities.

2.18.3 Avoidance, Minimization, and/or Mitigation Measures The following avoidance and minimization measures will reduce potentially significant indirect impacts, including stormwater runoff and sedimentation, to the Napa River.

AMM BIO-1.1: A spill prevention plan shall be prepared describing measures to be taken to minimize the risk of fluids or other materials used during construction (e.g., oils, transmission and hydraulic fluids, cement, fuel) from entering the Napa River or contaminating adjacent riparian areas.

In addition to a spill prevention plan, a cleanup protocol shall be developed before construction begins and will be implemented in case of a spill. The spill prevention plan and cleanup protocol shall be submitted to the Caltrans Engineer prior to construction.

AMM BIO-1.2: Stockpiling of materials, including portable equipment, vehicles and supplies (e.g., chemicals), will be restricted to the designated construction staging areas.

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2.19 Animal Species

2.19.1 Regulatory Setting
Many state and federal laws regulate impacts to wildlife. The U.S. Fish and Wildlife Service (USFWS), the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA Fisheries), and the California Department of Fish and Wildlife (CDFW) are responsible for implementing these laws. This section discusses potential impacts and permit requirements associated with animals not listed or proposed for listing under the federal or state Endangered Species Act. Species listed or proposed for listing as threatened or endangered are discussed in Section 2.20 Threatened and Endangered Species, below. All other special-status animal species are discussed here, including CDFW fully protected species and species of special concern, and USFWS or NOAA Fisheries candidate species.

Federal laws and regulations relevant to wildlife include the following:
• National Environmental Policy Act
• Migratory Bird Treaty Act (MBTA)
• Fish and Wildlife Coordination Act
State laws and regulations relevant to wildlife include the following:
• California Environmental Quality Act
• Sections 1600 – 1603 of the California Fish and Game Code • Sections 4150 and 4152 of the California Fish and Game Code

2.19.2 Affected Environment
The information in this section is based primarily on an NES(MI) (August 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference.

A copy of this study is available for review at the locations listed inside the front cover of this document.

The Migratory Bird Treaty Act and California Fish and Game Code protect migratory birds, including their eggs, nests, and young. The killing or harassment of such birds, including activities that may result in the abandonment of active nests during the nesting season (generally, February 1st through October 31st), is prohibited. Roosting bats are protected under the California Fish and Game Commission.

Trees within the Project area could provide nesting habitat for migratory birds, nesting birds, raptors, and roosting bats.

2.19.3 Environmental Consequences
The Project will result in tree removal. Trees to be removed would consist of street trees and landscape trees within the existing urban environment. As previously discussed in Section 2.18 Natural Communities, the only sensitive habitat in the project vicinity is

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riparian habitat along the northern boundary of the proposed staging area. No tree removal would occur within the riparian habitat adjacent to the proposed staging area.

The primary habitat value provided by trees to be removed would be for nesting birds and bats. Impacts to nesting birds and bats are discussed below.

Construction activities during the bird breeding season could result in the incidental loss of fertile eggs or nestlings, or otherwise lead to nest abandonment. Disturbance that causes abandonment and/or loss of reproductive effort is considered a taking by the CDFW. Any loss of fertile eggs, nesting raptors, or any activities resulting in nest abandonment would constitute an impact. Construction activities such as tree removal and site grading that disturb a nesting bird or raptor on-site or immediately adjacent to the construction zone would also constitute an impact. Potential impacts to nesting birds would be minimized and avoided with implementation of PF BIO-1.1 Tree removal could also potentially impact roosting bats. Lighting during potential night work could also potentially impact roosting bats, however, implementation of AMM VIS-

1.4 would require that construction lighting be limited through the use of directional lighting, shielding, or other methods. Therefore, lighting impacts to roosting bats would be minimized.

No-Build Alternative
No tree removal would occur under the No-Build Alternative and thus, the No-Build Alternative would not affect animal species including nesting migratory birds and roosting bats.

2.19.4 Avoidance, Minimization, and/or Mitigation Measures The Project shall implement the following measures for the purpose of avoiding and minimizing impacts to nesting migratory birds and roosting bats.

AMM BIO-2.1: The removal of any trees or structures containing suitable bat roosting habitat shall be scheduled to avoid the maternity roost season. To the extent feasible, activities should be restricted to the period between August 31 and April 15.

AMM BIO-2.2: If seasonal avoidance is not possible, within 10 days prior to the start of work, a roosting bat survey shall be performed by a qualified biologist to determine if potential bat roosts or roosting habitat is present on the Project site or within a zone of influence (i.e., 50 feet) and if any avoidance measures are necessary to avoid impacts on bats. If roosting bats or signs of roosting bats are observed, a qualified biologist shall develop a roost deterrent and/or roost exclusion plan.

The deterrent/exclusion plan shall include measures to avoid bats potentially using bat tree roost habitat within the Project limits.

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2.20 Threatened and Endangered Species

2.20.1 Regulatory Setting
The primary federal law protecting threatened and endangered species is the Federal Endangered Species Act (FESA): 16 United States Code (USC) Section 1531, et seq.

See also 50 Code of Federal Regulations (CFR) Part 402. This act and later amendments provide for the conservation of endangered and threatened species and the ecosystems upon which they depend. Under Section 7 of this act, federal agencies, such as the Federal Highway Administration (FHWA) (and Caltrans, as assigned), are required to consult with the U.S. Fish and Wildlife Service (USFWS) and the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA Fisheries) to ensure that they are not undertaking, funding, permitting, or authorizing actions likely to jeopardize the continued existence of listed species or destroy or adversely modify designated critical habitat. Critical habitat is defined as geographic locations critical to the existence of a threatened or endangered species. The outcome of consultation under Section 7 may include a Biological Opinion with an Incidental Take Statement or a Letter of Concurrence. Section 3 of FESA defines take as “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect or any attempt at such conduct.” California has enacted a similar law at the state level, the California Endangered Species Act (CESA), California Fish and Game Code Section 2050, et seq. CESA emphasizes early consultation to avoid potential impacts to rare, endangered, and threatened species and to develop appropriate planning to offset project-caused losses of listed species populations and their essential habitats. The California Department of Fish and Wildlife (CDFW) is the agency responsible for implementing CESA. Section 2080 of the California Fish and Game Code prohibits “take” of any species determined to be an endangered species or a threatened species. Take is defined in Section 86 of the California Fish and Game Code as “hunt, pursue, catch, capture, or kill, or attempt to hunt, pursue, catch, capture, or kill.” CESA allows for take incidental to otherwise lawful development projects; for these actions an incidental take permit is issued by CDFW. For species listed under both FESA and CESA requiring a Biological Opinion under Section 7 of FESA, the CDFW may also authorize impacts to CESA species by issuing a Consistency Determination under Section 2080.1 of the California Fish and Game Code.

Another federal law, the Magnuson-Stevens Fishery Conservation and Management Act of 1976, was established to conserve and manage fishery resources found off the coast, as well as anadromous species and Continental Shelf fishery resources of the United States, by exercising (A) sovereign rights for the purposes of exploring, exploiting, conserving, and managing all fish within the exclusive economic zone established by Presidential Proclamation 5030, dated March 10, 1983, and (B) exclusive fishery management authority beyond the exclusive economic zone over such anadromous species, Continental Shelf fishery resources, and fishery resources in special areas.

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2.20.2 Affected Environment
The information in this section is based primarily on an NES(MI) (August 2024) that was prepared for the Project. This study is incorporated into this Final EIR/EA by reference.

A copy of this study is available for review at the locations listed inside the front cover of this document.

The California Natural Diversity Database (CNDDB) identified 25 special-status wildlife species that have the potential to occur in the vicinity of the Project site.30 Out of the 25 species, five species were determined to have the potential to occur within or adjacent to the Project site due to the presence of marginally suitable habitat. The five species with the potential to occur within or adjacent to the Project limits include the green sturgeon (Acipenser medirostris), steelhead salmon (Oncorhynchus mykiss irideus), chinook salmon (Oncorhynchus tshawytscha), longfin smelt (Spirinchus thaleichthys), and western pond turtle (emys marmorata). These species are discussed in further detail below.

Green Sturgeon
Green sturgeon is a federally threatened anadromous31 fish. During spawning runs, adult fish arrive in the San Francisco Bay between mid-February and early May and then migrate up the Sacramento River. Spawning mainly occurs in cool sections of the upper Sacramento River with deep, turbulent flows and gravel. In the fall, adults move back down the river to the ocean while juveniles remain in the river for approximately five years before moving downstream. Although suitable habitat exists within the Napa River for green sturgeon, they are not typically observed there. Green sturgeon have a very low potential to occur adjacent to the Project limits.

Steelhead Salmon
Steelhead salmon are a federal threatened anadromous fish. Steelhead salmon spawn below natural and manmade impassable barriers from the Russian River to and including Aptos Creek, and all drainages of San Francisco and San Pablo Bays eastward to Chipps Island at the confluence of the Sacramento and San Joaquin Rivers. After maturing in the ocean, adult steelhead return to the Napa River typically between January and March, but upstream migration can occur as late as May in years with abundant late-season rainfall. As most of this migration is nocturnal, not much is known about the specific movement patterns of adult steelhead within the Napa River watershed. Steelhead spawning has been observed frequently in the mainstream Napa River in recent years, although it appears to be associated with dry years when access to preferred tributary spawning grounds is limited by low seasonal streamflow. Juvenile

30 Species included in this analysis were based on the 3- and 5-mile CNDDB query and the National Marine Fisheries Service and USFWS’ Information for Planning and Consultation species lists. Other databases, such as CalFish or PISCES were not consulted. Species with listing status below Species of Special Concern, such as those on the CDFW Watch List, were not considered as they are not afforded the same level of protection.
31 Anadromous fish migrate from freshwater where they hatch to the ocean where they spend most of their lives and grow large before returning to freshwater to spawn. Source: North Pacific Anadromous Fish Commission. “Species: What is an Anadromous Fish?”. Accessed February 12, 2025. https://www.npafc.org/species/

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steelhead remain in freshwater for one or more years before migrating to the ocean.

Steelhead salmon have high potential to occur within the Napa River due to suitable habitat and recent observation.

Chinook Salmon
Chinook salmon are a federally endangered anadromous fish. Late fall-run chinook are found primarily in the Sacramento River, where most spawning and rearing of juveniles takes place in the reach between the Red Bluff Diversion Dam and Redding below the dam. The historical abundance and distribution of chinook salmon in the Napa River is not well understood. In the 2000s, juvenile salmon were regularly collected from the Napa River and adult spawning was observed in most years, suggesting recolonization within the river. Spawning chinook salmon return to the Napa River in the fall, typically around late September and early October. Adult fish will hold in the lower river and estuary for a month or more and will swim upstream from the estuary with the first rains for spawning. Spawning in the Napa River occurs between November and January, but may be observed as early as September. Young chinook salmon remain in the Napa River until they are approximately three to four inches long and travel to the estuary, which occurs throughout the spring, peaking in May. Chinook salmon have high potential to occur within the Napa River due to suitable habitat and recent observations.

Longfin Smelt
Longfin smelt are an anadromous, federal candidate for listing and are state threatened.

Within areas north of the Bay-Delta, longfin smelt use a variety of habitat including coastal lagoons, bays, estuaries, sloughs, tidal freshwater streams, and offshore.

Especially during wet years, the Napa River and its estuary may be an important spawning and rearing area for longfin smelt. Smelt spawn from November through May, with a peak from February through April. Densities of longfin smelt in the Napa River have been observed to be low compared to other freshwater rivers and tributaries in the region. However, there is still a high potential for longfin smelt to occur within the Napa River due to the presence of suitable habitat.

Western Pond Turtle
The western pond turtle (WPT) is a federal candidate for listing and a State Species of Special Concern. WPT prefer aquatic habitat with refugia such as undercut banks and submerged vegetation and require emergent basking sites such as mud banks, rocks, logs, and root wads. WPT have been observed in slow-moving rivers, streams, lakes, reservoirs, wetlands, stock ponds, and sewage treatment plants. They also regularly utilize upland terrestrial habitats, most often during summer and winter, especially for nesting, overwintering, and overland dispersal. Females have been found as far as 500 meters from a watercourse in search of suitable nesting habitat.

The northern boundary of the proposed staging area abuts riparian vegetation and is approximately 50 feet south of the Napa River. Suitable habitat for WPT occurs within the Napa River. At the proposed staging area, the bank offers marginal overland travel as it is mostly too steep for incidental travel. The closest CNDDB records of a WPT are dated 2017 at Napa College, approximately 1.3 miles south of the Project limits. For

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these reasons, there is potential for WPT to occur adjacent to the proposed staging area.

2.20.3 Environmental Consequences
A summary of all the USFWS and NOAA Fisheries species considered and the effect findings for each species is provided in Table 2.20-1.

Table 2.20-1: FESA Preliminary Effect Findings
Common Name Scientific Name Status Effect Finding
Effect Finding
for Critical
Habitat (if
applicable)
Conservancy fairy
shrimp
Branchinecta
conservation
FE No effect N/A
Monarch-California
overwintering
population
Danaus plexippus pop. 1 FC No effect N/A
California freshwater
shrimp
Syncaris pacifica FE No effect N/A
Green sturgeon
Southern Distinct
Population Segment
(sDPS)
Acipenser medirostris
pop. 1
FT No effect N/A
Steelhead salmon –
California coast Distinct
Population Segment
(DPS)
Oncorhynchus mykiss
irideus pop. 8
FT No effect N/A
Chinook salmon Central
Valley fall/late fall-run
Evolutionary Significant
Unit (ESU)
Oncorhynchus
tshawytscha pop. 13
FE No effect N/A
Longfin smelt Spirinchus thaleichthys FC No effect N/A
Western spadefoot Spea hammondii FC No effect N/A
California red-legged
frog
Rana draytonii FT No effect N/A
Western pond turtle Emys marmorata FC No effect N/A
California least tern Sterna antillarum browni FE No effect N/A Northern spotted owl Strix occidentalis caurina FT No effect N/A Salt-marsh harvest
mouse
Reithrodontomys
raviventris
FE No effect N/A
*Status: Federally Endangered (FE); Federally Threatened (FT); Federal Candidate (FC) Five special-status species were determined to have the potential to occur adjacent to the Project limits: green sturgeon, steelhead salmon, chinook salmon, longfin smelt, and WPT. All five of these species have the potential to occur within the Napa River, adjacent to the northern boundary of the proposed staging area and WPT also has the potential to occur in riparian habitat between the Napa River and proposed staging area. The proposed staging area would be isolated from the primary Project construction and would be used primarily as a laydown area for equipment. The majority of the Project limits are separated from the Napa River by approximately 275 feet of developed, urban land. For these reasons, the Project would not directly affect the Napa

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River and any of the associated special-status fish species. Any potential indirect affects to special-status fish species would be avoided through incorporation of construction BMPs and post-construction stormwater treatment controls (see Section 2.11 Water Quality and Stormwater Runoff) and implementation of AMM BIO-1.1 through AMM BIO-1.2 (see Section 2.18 Natural Communities) to prevent runoff pollution.

The project is expected to have no effect on fish species and western pond turtle because the project will not occur within habitat for these species and because of the distance between the Napa River and the construction area, which is sufficient to eliminate potential indirect effects. The staging area will incorporate AMMs to prevent indirect impacts to these species to no effect.

The Project would not result in the hunting, catch, capture, or killing or an attempt to hunt, catch, capture, or kill CESA species.

No-Build Alternative
The No-Build Alternative would not result in any affects on threatened and endangered species.

2.20.4 Avoidance, Minimization, and/or Mitigation Measures The Project shall implement the following measures for the purpose of avoiding and minimizing impacts to special-status species.

AMM BIO-3.1: Before any ground-disturbing activities begin, a qualified biologist, defined as a person who possesses, at minimum, a bachelor's degree in biological sciences, zoology, botany, ecology, or another closely- related field, and who is familiar with western pond turtle, shall conduct a training session for all on-site project personnel. At a minimum, the training will include a description of western pond turtle terrestrial behavior, as well as nesting birds, roosting bats—specifically, the pallid bat, the importance of these species, legal protections, the measures that are being implemented to avoid and minimize impacts as they relate to the Project, and the boundaries within which work may occur.

All construction personnel, equipment, and vehicle movement shall be confined to designated construction and staging areas.

AMM BIO-3.3: Plastic monofilament netting (erosion control matting) or similar material shall not be used because wildlife may become entangled or trapped in it. Acceptable substitutes include coconut coir matting or tackifier hydroseeding compounds.

AMM BIO-3.4: To prevent special-status species from entering the construction staging area, exclusion fencing (e.g., silt fence) shall be constructed in

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strategic locations in and around all work areas within 100 feet of all aquatic features. Exclusion fencing shall be installed prior to the start of Project-related activities and should be placed within 10 feet of the edge of work areas. Permittee shall maintain the barrier throughout all construction activities.

A Qualified Biologist shall inspect the area prior to fence installation.

The interior and exterior of the exclusion fencing shall be inspected by WEAP-trained crews at least once daily before 9:00 a.m. each day to ensure that no special-status species are trapped against the fencing, where they could desiccate or be predated upon. The Project proponent shall maintain and repair the barrier immediately to ensure that it is functional and without defects. The barrier shall remain in place until project activities in that area have been completed and construction equipment has been removed from the site.

If wildlife is found along the fence, a Qualified Biologist shall be consulted. The Project proponent shall avoid damage to small mammal burrows to the maximum extent possible during installation of the exclusion fencing. The Project proponent shall also ensure that silt fencing and/or other erosion control methods used to prevent sediment or other debris from passing into aquatic habitat that is within 100 feet of Project construction activities does not create a barrier to special- status species movement.

AMM BIO-3.5: Crews shall check for wildlife under all vehicles, equipment, materials, or otherwise suitable locations for wildlife, such as western pond turtle, to hide. Workers shall inspect under vehicles and equipment for wildlife before vehicles and equipment are moved or have been idle for five minutes. If wildlife is present, they shall be allowed to move out of the construction area under their own volition.

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Chapter 3 California Environmental Quality
Act (CEQA) Evaluation

3.1 DETERMINING SIGNIFICANCE UNDER CEQA
The Project is subject to federal and state environmental review requirements because the City of Napa proposes the use of federal funds from the Federal Highway Administration (FHWA) and/or the project requires an approval from FHWA. Project documentation, therefore, has been prepared in compliance with both the California Environmental Quality Act (CEQA) and the National Environmental Policy Act (NEPA).

The City of Napa is the project proponent and the lead agency under CEQA. FHWA’s responsibility for environmental review, consultation, and any other actions required by applicable Federal environmental laws for this project are being, or have been, carried out by Caltrans pursuant to 23 United States Code Section 327 (23 USC 327) and the Memorandum of Understanding dated May 27, 2022, and executed by FHWA and Caltrans.

One of the primary differences between NEPA and CEQA is the way significance is determined. Under NEPA, significance is used to determine whether an EIS, or a lower level of documentation, will be required. NEPA requires that an EIS be prepared when the proposed federal action (project) as a whole has the potential to “significantly affect the quality of the human environment.” The determination of significance is based on context and intensity. Some impacts determined to be significant under CEQA may not be of sufficient magnitude to be determined significant under NEPA. Under NEPA, once a decision is made regarding the need for an EIS, it is the magnitude of the impact that is evaluated and no judgment of its individual significance is deemed important for the text. NEPA does not require that a determination of significant impacts be stated in the environmental documents.

CEQA, on the other hand, does require the lead agency to identify each “significant effect on the environment” resulting from the project and ways to mitigate each significant effect. If the project may have a significant effect on any environmental resource, then an EIR must be prepared. Each and every significant effect on the environment must be disclosed in the EIR and mitigated if feasible. In addition, the CEQA Guidelines list a number of “mandatory findings of significance,” which also require the preparation of an EIR. There are no types of actions under NEPA that parallel the findings of mandatory significance of CEQA. This chapter discusses the effects of this project and CEQA significance.

3.2 CEQA ENVIRONMENTAL CHECKLIST
This checklist identifies physical, biological, social, and economic factors that might be affected by the proposed project. In many cases, background studies performed in connection with the projects will indicate that there are no impacts to a particular resource. A NO IMPACT answer in the last column reflects this determination. The words "significant" and "significance" used throughout the following checklist are related

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to CEQA, not NEPA, impacts. The questions in this form are intended to encourage the thoughtful assessment of impacts and do not represent thresholds of significance.

Project features, which can include both design elements of the project, and standardized measures that are applied to all or most Caltrans projects such as Best Management Practices (BMPs) and measures included in the Standard Plans and Specifications or as Standard Special Provisions, are considered to be an integral part of the project and have been considered prior to any significance determinations documented below; see Chapters 1 and 2 for a detailed discussion of these features.

The annotations to this checklist are summaries of information contained in Chapter 2 in order to provide the reader with the rationale for significance determinations; for a more detailed discussion of the nature and extent of impacts, please see Chapter 2. This checklist incorporates by reference the information contained in Chapters 1 and 2.

3.2.1 Aesthetics
Except as provided in Public Resources Code
Section 21099, would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Have a substantial adverse effect on a scenic
vista?
b) Substantially damage scenic resources,
including, but not limited to, trees, rock
outcroppings, and historic buildings within a
state scenic highway?

c) In non-urbanized areas, substantially
degrade the existing visual character or quality
of public views of the site and its surroundings?
(Public views are those that are experienced
from a publicly accessible vantage point). If the
project is in an urbanized area, would the
project conflict with applicable zoning and other
regulations governing scenic quality?

d) Create a new source of substantial light or
glare which would adversely affect day or
nighttime views in the area?

CEQA Significance Determinations for Aesthetics
a) Would the Project have a substantial adverse effect on a scenic vista? No Impact. There are no designated scenic vistas in the Project vicinity. Scenic vistas identified in the City of Napa 2040 General Plan EIR include the Vaca Range, Mayacamas Mountains, and views of agricultural fields and vineyards in the countryside adjacent to the City. The Project is located within an urban area of the City and would

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not adversely affect views from the Vaca Range or Mayacamas Mountains or views of agricultural fields or vineyards.
b) Would the Project substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway?
No Impact. The project would result in the removal of existing trees and other stands of natural vegetation and would result in the removal of one residence at 801 Silverado Trail listed on the City of Napa Historic Resources Inventory. SR 121 within the Project limits is listed as an eligible, but not officially designated, state scenic highway. The Project would not make any changes that would affect scenic resources visible from an officially designated state scenic highway.
c) In non-urbanized areas, substantially degrade the existing visual character or quality of public views of the site and its surroundings? (Public views are those that are experienced from a publicly accessible vantage point). If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality?
Less than Significant Impact. The Project is located within an urban area of the City of Napa. The Project would comply with applicable regulations governing scenic quality.

The Project would provide new landscaping and would be constructed in compliance with PF VIS-1.1 through 1.4 and the AMMs described in Section 2.8 Visual/Aesthetics. d) Would the Project create a new source of substantial light or glare which would adversely affect day or nighttime views in the area?
Less than Significant Impact. New overhead lights would be added which would increase the nighttime light levels in the neighborhoods immediately adjacent to the Project limits. The new overhead lights would not result in a substantial new source of light, as overhead lights along roadways are a common feature in residential neighborhoods. Light impacts from overhead lights would be further reduced by AMM VIS-1.5, which would require that shielding be incorporated to limit light trespass.

3.2.2 Agriculture and Forestry Resources
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Convert Prime Farmland, Unique Farmland,
or Farmland of Statewide Importance
(Farmland), as shown on the maps prepared
pursuant to the Farmland Mapping and
Monitoring Program of the California Resources
Agency, to non-agricultural use?

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Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
b) Conflict with existing zoning for agricultural
use, or a Williamson Act contract?
c) Conflict with existing zoning for, or cause
rezoning of, forest land (as defined in Public
Resources Code section 12220(g)), timberland
(as defined by Public Resources Code section
4526), or timberland zoned Timberland
Production (as defined by Government Code
section 51104(g))?

d) Result in the loss of forest land or conversion
of forest land to non-forest use?
e) Involve other changes in the existing
environment which, due to their location or
nature, could result in conversion of Farmland,
to non-agricultural use or conversion of forest
land to non-forest use?

CEQA Significance Determinations for Agriculture and Forestry Resources a) Would the Project convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use?
And
b) Would the Project conflict with existing zoning for agricultural use, or a Williamson Act contract?
And
c) Would the Project conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code section 12220(g)), timberland (as defined by Public Resources Code section 4526), or timberland zoned Timberland Production (as defined by Government Code section 51104(g))? And
d) Would the Project result in the loss of forest land or conversion of forest land to non-forest use?

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And
e) Would the Project involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland, to non- agricultural use or conversion of forest land to non-forest use? No Impact. The Project area is urbanized and developed. There are no farmlands or timberlands located within or adjacent to the Project limits. No lands mapped as Prime Farmland, Unique Farmland, or Farmland of Statewide Importance are located in the Project vicinity. No parcels subject to a Williamson Act contract or zoned for agricultural use, timberland, or forest land are present within or adjacent to the Project limits. The Project would not convert any agricultural or forest land to other uses.

3.2.3 Air Quality
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Conflict with or obstruct implementation of
the applicable air quality plan?
b) Result in a cumulatively considerable net
increase of any criteria pollutant for which the
project region is non- attainment under an
applicable federal or state ambient air quality
standard?

c) Expose sensitive receptors to substantial
pollutant concentrations?
d) Result in other emissions (such as those
leading to odors) adversely affecting a
substantial number of people?

CEQA Significance Determinations for Air Quality
a) Would the Project conflict with or obstruct implementation of the applicable air quality plan?
No Impact. As discussed in Section 2.15 Air Quality, the Project conforms to the Clean Air Plan. As shown in Table 2.15-4 the long-term operational emissions of air pollutants would be the same under the Build Alternative and the No-Build Alternative. b) Would the Project result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard?

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Less than Significant Impact. Per the Air District’s CEQA Air Quality Guidelines, air pollution by its nature is largely a cumulative impact. No single project is sufficient in size, by itself, to result in nonattainment of ambient air quality standards. If a project exceeds the identified significance thresholds, its emissions would be cumulatively considerable, resulting in significant adverse air quality impacts to the region’s existing air quality conditions. As discussed above, the Build Alternative would not increase operational emissions as compared to the No-Build Alternative as the number of vehicle trips in the area will not change with implementation of the Project. As shown in Table

2.15-6, construction of the Project would result in criteria air pollutant emissions. The Project construction emissions would not exceed the Air District’s construction thresholds for ROG, NOx, and PM2.5 of 54 pounds per day or PM10 threshold of 82 pounds per day. Implementation of AMM AIR-1.1 to AIR-1.2 and PF AIR-1.1 to AIR-1.2 would reduce construction emissions. As a result, the proposed Project would not result in a cumulatively considerable net increase of any criteria pollutant for which the region is non-attainment.
c) Would the Project expose sensitive receptors to substantial pollutant concentrations?
Less than Significant Impact. The Project would not result in an increase in VMT or other permanent sources of air pollutants. Therefore, Project operation would not expose nearby sensitive receptors to substantial pollutant concentrations. The Project would introduce new sources of TACs during construction that would affect nearby sensitive receptors. The primary health risk impacts associated with construction would be cancer risks associated with diesel exhaust, which is a known TAC, and exposure to high ambient concentrations of dust (i.e., PM2.5).

As discussed in Section 2.15 Air Quality, the Project would have a less than significant impact for criteria pollutants and therefore, the Project would also result in no adverse health effect. Additionally, the Project would be required to implement AMM AIR-1.1 and AIR-1.2 and PF AIR 1.1 to AIR 1.2 as required by Caltrans’ Standard Specifications and the Air District’s recommended BMPs, which would further reduce potential health risk impacts by reducing construction equipment exhaust emissions and fugitive dust generated during ground-disturbing activities.
d) Would the Project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
Less than Significant Impact. The Project would not include any odor causing operations, and any odors emitted by diesel equipment during construction would be temporary and localized.

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3.2.4 Biological Resources
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Have a substantial adverse effect, either
directly or through habitat modifications, on any
species identified as a candidate, sensitive, or
special status species in local or regional plans,
policies, or regulations, or by the California
Department of Fish and Wildlife, U.S. Fish and
Wildlife Service, or NOAA Fisheries?

b) Have a substantial adverse effect on any
riparian habitat or other sensitive natural
community identified in local or regional plans,
policies, regulations or by the California
Department of Fish and Wildlife or U.S. Fish
and Wildlife Service?

c) Have a substantial adverse effect on state or
federally protected wetlands (including, but not
limited to, marsh, vernal pool, coastal, etc.)
through direct removal, filling, hydrological
interruption, or other means?

d) Interfere substantially with the movement of
any native resident or migratory fish or wildlife
species or with established native resident or
migratory wildlife corridors, or impede the use of
native wildlife nursery sites?

e) Conflict with any local policies or ordinances
protecting biological resources, such as a tree
preservation policy or ordinance?
f) Conflict with the provisions of an adopted
Habitat Conservation Plan, Natural Community
Conservation Plan, or other approved local,
regional, or state habitat conservation plan?

CEQA Significance Determinations for Biological Resources a) Would the Project have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife, U.S. Fish and Wildlife Service, or NOAA Fisheries?

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Less than Significant Impact. No special-status plant species would be affected by the Project due to a lack of suitable habitat within and adjacent to the Project limits. As discussed in Section 2.20 Threatened and Endangered Species, there are five special- status species that have the potential to occur in the Napa River adjacent to the proposed staging area: green sturgeon, steelhead salmon, chinook salmon, longfin smelt, and WPT. Additionally, trees within and adjacent to the Project limits could provide habitat for nesting birds and roosting bats. Project construction activities could result in impacts to these species, however, with incorporation of the AMMs described in Section 2.18 Natural Communities, 2.19 Animal Species, and 2.20 Threatened and Endangered Species, potential impacts would be reduced to a less than significant level.
b) Would the Project have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service?
Less than Significant Impact. As discussed in Section 2.18 Natural Communities, there is riparian habitat along the northern boundary of the proposed staging area.

There are no other sensitive habitats or communities within or adjacent to the Project limits. The Project would not result in any direct impacts to the riparian habitat but Project construction activities could result in indirect impacts if construction fluids are spilled or equipment otherwise disturbs the habitat. However, with incorporation of AMM BIO-1.1 to 1.2, Project construction impacts would be reduced to a less than significant level.
c) Would the Project have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? Less than Significant Impact. There are no wetlands within the Project limits. There is one roadside drainage ditch along the southern end of SR 121, outside the Project limits. The Project would not directly impact the drainage ditch or any other aquatic resource through direct removal, filling, or hydrological interruption. Indirect impacts associated with runoff are discussed in Section 2.11 Water Quality and Stormwater Runoff and Section 2.18 Natural Communities. With incorporation of the AMMs described in these sections, the Project would not have a substantial adverse effect on the roadside drainage or any other aquatic resources.
d) Would the Project interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? Less than Significant Impact. As described under checklist question a), the Project has the potential to impact special-status fish species that migrate up the Napa River to spawn, migratory birds, and bat roosts. However, with implementation of PF BIO-1.1 and the AMMs described in Section 2.18 Natural Communities, 2.19 Animal Species, and 2.20 Threatened and Endangered Species, impacts to migratory fish and wildlife,

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wildlife corridors, and wildlife nursery sites would be reduced to a less than significant level.
e) Would the Project conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? Less than Significant Impact. The Project would remove existing street trees. The Project would comply with the City of Napa Municipal Code Chapter 12.44.030 regarding the planting and removal of street trees. The Director of Community Development may remove or cause to be removed any hazardous tree, hedge, shrub, or plant from any city property or within a public right-of-way or where necessary for any engineering reason. The Project includes the installation of new landscaping and street trees within the Project limits. The Project would comply with the applicable City ordinances and policies and would therefore have a less than significant impact. f) Would the Project conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan?
No Impact. No Habitat Conservation Plans (HCPs) or Natural Community Conservation Plans (NCCPs) exist in the City of Napa. Therefore, the proposed Project would have no impact related to conflicting with provisions of an adopted HCP or NCCP.

3.2.5 Cultural Resources
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Cause a substantial adverse change in the
significance of a historical resource pursuant to
in §15064.5?

b) Cause a substantial adverse change in the
significance of an archaeological resource
pursuant to §15064.5?

c) Disturb any human remains, including those
interred outside of dedicated cemeteries?
CEQA Significance Determinations for Cultural Resources a) Would the Project cause a substantial adverse change in the significance of a historical resource pursuant to in §15064.5?
Significant and Unavoidable Impact. As described in Section 2.9 Cultural Resources, the Project would demolish the existing residence at 801 Silverado Trail. The residence

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is currently listed on the City’s HRI as a contributor to the East Napa Historic District.

Therefore, the residence would be considered a historical resource pursuant to CEQA Guidelines Section 15064.5. According to CEQA Guidelines Section 15064.5(b), a “project with an effect that may cause a substantial adverse change in the significance of an historical resource is a project that may have a significant effect on the environment.” Substantial adverse change is defined as: “physical demolition, destruction, relocation, or alteration of the resource or its immediate surroundings such that the significance of an historical resource would be materially impaired.”32 The Project design team considered the feasibility of relocating the residential structure as part of the Project, however, given the style of construction and foundation type it was determined the structure could not feasibly be moved. The Project would demolish the existing residence at 801 Silverado Trail, making the property no longer eligible for listing in the City’s HRI and impacting the integrity of the East Napa Historic District by removing one of its contributing properties. Therefore, the Project would result in a significant impact on historical resources according to CEQA Guidelines Section 15064.5. MM CULT-1.1 would require the Project sponsor to document the East Napa Historic District, including 801 Silverado Trail as a contributing resource prior to its demolition. With implementation of MM CULT-1.1, the East Napa Historic District is anticipated to remain eligible for listing in the NRHP. However, the Project’s impact of demolishing 801 Silverado Trail, a CEQA historical resource, would remain significant and unavoidable.
b) Would the Project cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5?
And
c) Would the Project disturb any human remains, including those interred outside of dedicated cemeteries?
No Impact. As discussed in Section 2.9 Cultural Resources, the Project area ranges from low to high sensitivity for buried archaeological resources. There is potential for the Project to encounter buried archaeological resources, including human remains, during ground-disturbing construction activities. However, incorporation of PF CULT-1.1 and PF CULT-1.2 would ensure that any buried archaeological resources or human remains that are inadvertently discovered during Project ground-disturbing activities are properly handled. For these reasons, the Project would not cause an adverse change in the significance of an archaeological resource or disturb human remains.

32 CEQA Guidelines Section 15064.5(b)(1).

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3.2.6 Energy
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Result in potentially significant environmental
impact due to wasteful, inefficient, or
unnecessary consumption of energy resources,
during project construction or operation?

b) Conflict with or obstruct a state or local plan
for renewable energy or energy efficiency?
CEQA Significance Determinations for Energy
a) Would the Project result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation?
And
b) Would the Project conflict with or obstruct a state or local plan for renewable energy or energy efficiency?
Less than Significant Impact. As discussed in Section 2.17 Energy, the Project would not result in a change in VMT and therefore would not result in an increase in vehicle fuel usage. The Project would not introduce any substantial new sources of energy consumption. Energy would not be used inefficiently, wastefully, or unnecessarily during Project operation or construction. The Project would comply with applicable renewable energy and energy efficiency plans and laws such as the City of Napa’s Construction and Demolition Debris Recycling Ordinance.

3.2.7 Geology and Soils
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Directly or indirectly cause potential
substantial adverse effects, including the risk of
loss, injury, or death involving:

i) Rupture of a known earthquake fault, as
delineated on the most recent Alquist-Priolo
Earthquake Fault Zoning Map issued by the
State Geologist for the area or based on

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Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
other substantial evidence of a known fault?
Refer to Division of Mines and Geology
Special Publication 42.
ii) Strong seismic ground shaking?
iii) Seismic-related ground failure, including
liquefaction?
iv) Landslides?
b) Result in substantial soil erosion or the loss
of topsoil?
c) Be located on a geologic unit or soil that is
unstable, or that would become unstable as a
result of the project, and potentially result in on-
or off-site landslide, lateral spreading,
subsidence, liquefaction or collapse?

d) Be located on expansive soil, as defined in
Table 18-1-B of the Uniform Building Code
(1994), creating substantial direct or indirect
risks to life or property?

e) Have soils incapable of adequately
supporting the use of septic tanks or alternative
waste water disposal systems where sewers
are not available for the disposal of waste
water?

f) Directly or indirectly destroy a unique
paleontological resource or site or unique
geologic feature?

CEQA Significance Determinations for Geology and Soils
a) Would the Project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving:

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i. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. ii. Strong seismic ground shaking?
iii. Seismic-related ground failure, including liquefaction? iv. Landslides?
Less than Significant Impact. The Project is not located within an Alquist-Priolo Fault Zone and there are no known earthquake faults crossing the Project limits. Therefore, the site is not subject to ground rupture. The Project would be subject to strong ground shaking in the event of an earthquake, particularly one located along the West Napa Fault. However, the Project would be constructed in accordance with City of Napa and Caltrans codes and standards and in accordance with the recommendations contained in the Project’s design-level geotechnical investigation to reduce the risk of damage from seismic activity.

Based on boring data collected on-site, there does not appear to be potential for liquefaction at the site. However, as required by AMM GEO-1.1., further testing will be required to verify liquefaction potential at the site. Liquefaction risks would be accounted for in the final design phase.

The majority of the Project site has low potential for landslides due to its relatively flat nature. The Tulocay Cemetery, adjacent to the east of the project limits, is mapped as having moderate potential for landslides. The Project would not exacerbate landslide potential risks at the site.
b) Would the Project result in substantial soil erosion or loss of topsoil? Less than Significant Impact. The Project site is relatively flat, lessening the chance for substantial erosion or siltation. Conformance with Caltrans and City of Napa civil, geotechnical engineering, and construction and post-construction stormwater BMPs (described further in Section 2.11 Water Quality) would further reduce any risk of substantial erosion or siltation to a less than significant level. c) Would the Project be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse? Less than Significant Impact. The majority of the Project site has low potential for landslides and the risk for lateral spreading, liquefaction, and soil collapse at the site is considered low based on data collected on-site. The Project is not underlain by soils that are unstable or would become unstable as a result of implementation of the Project.

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d) Would the Project be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property?
Less than Significant Impact. The majority of soils in the Project area have a low expansive potential. The western section of the Project limits is mapped as having a moderate expansive potential. As previously discussed, the Project would be completed in accordance with City of Napa and Caltrans codes and standards and in accordance with the recommendations contained in the Project’s design-level geotechnical investigation to reduce the risk of damage from expansive soils. e) Would the Project have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water?
No Impact. The Project would not include the use of a septic tank or alternative wastewater disposal systems.
f) Would the Project directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?
Less than Significant Impact. As discussed in Section 2.13 Paleontology of this Final EIR/EA, based on the lack of known paleontological resources within 10 miles of the Project site and the level of ground disturbance required by the Project, it is unlikely that construction would encounter any undisturbed pre-Holocene sediments with fossils.

3.2.8 Greenhouse Gas Emissions
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Generate greenhouse gas emissions, either
directly or indirectly, that may have a significant
impact on the environment?

b) Conflict with an applicable plan, policy or
regulation adopted for the purpose of reducing
the emissions of greenhouse gases?

CEQA Significance Determinations for Greenhouse Gas Emissions a) Would the Project generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? Less than Significant Impact. GHG emissions associated with the proposed Build Alternative would occur over the short-term from construction activities, consisting primarily of emissions from equipment exhaust and worker and vendor trips. The Project

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would result in approximately 1,001 MT of CO2e per year and a total of 1,501 MT of CO2e for the whole duration of construction.33 Neither the Air District nor the City of Napa recommend a GHG emissions threshold of significance for construction emissions. As described in Section 2.15 Air Quality, the Project would be required to implement control measures during construction that would limit emissions generated by equipment used. For these reasons, Project construction would not generate a significant amount of GHG emissions.

As previously described in Section 2.15 Air Quality, the Project would not result in a change in VMT for the Project area and would not include any stationary sources of GHG emissions. Additionally, the Project may result in less GHG emissions due to reduced vehicle delay (e.g., idling) at the intersection. For these reasons, Project operation would not generate a significant amount of GHG emissions. b) Would the Project conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases? Less than Significant Impact. At the time of preparation of this Final EIR/EA, the City of Napa has not adopted a GHG Reduction Strategy. The Project would result in no net permanent increase in GHG emissions and could reduce GHG emissions by reducing vehicle idling at the Project intersection. Additionally, by providing a new shared-use path through the Project intersection the Project would be consistent with the 2017 Clean Air Plan Transportation Control Measure TR9: Bicycle and Pedestrian Access and Facilities, which encourages planning for bicycle and pedestrian facilities.

Therefore, the Project would not conflict with the 2017 Clean Air Plan or another plan, policy, or regulation adopted for the purpose of reducing GHG emissions.

3.2.9 Hazards and Hazardous Materials
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Create a significant hazard to the public or
the environment through the routine transport,
use, or disposal of hazardous materials?

b) Create a significant hazard to the public or
the environment through reasonably
foreseeable upset and accident conditions
involving the release of hazardous materials
into the environment?

33 Illingworth & Rodkin, Inc. Air Quality Report: Intersection Improvements at Silverado Trail (SR 121)/Third Street/Coombsville Road/East Avenue. Appendix C: Cal-CET2021 Construction Emissions Calculation. October 2024.

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Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
c) Emit hazardous emissions or handle
hazardous or acutely hazardous materials,
substances, or waste within one-quarter mile of
an existing or proposed school?

d) Be located on a site which is included on a
list of hazardous materials sites compiled
pursuant to Government Code Section 65962.5
and, as a result, would it create a significant
hazard to the public or the environment?

e) For a project located within an airport land
use plan or, where such a plan has not been
adopted, within two miles of a public airport or
public use airport, would the project result in a
safety hazard or excessive noise for people
residing or working in the project area?

f) Impair implementation of or physically
interfere with an adopted emergency response
plan or emergency evacuation plan?
g) Expose people or structures, either directly or
indirectly, to a significant risk of loss, injury or
death involving wildland fires?

CEQA Significance Determinations for Hazards and Hazardous Materials a) Would the Project create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? Less than Significant Impact. Construction of the proposed Project would require the temporary use of gasoline-, diesel- or electric-powered equipment; as well as the use of hazardous materials including petroleum products, lubricants, cleaners, paints, and solvents. Once operational, these materials would also be utilized for occasional maintenance on an as-needed basis (likely not more than once each year). These materials would be used in accordance with relevant federal, state, and local laws. If used as directed, these materials would not pose a hazard to the environment or workers or persons in the vicinity.

Similar to existing conditions, hazardous materials could be transported by commercial and/or private vehicles along the Project roadways. Vehicles operating on public roads are subject to all local, state, and federal regulations governing the transport of hazardous materials. This includes, but is not limited to, the Hazardous Materials Transportation Act. Additionally, all public roadways constructed within the City and County of Napa are required to adhere to all applicable roadway design standards and

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regulations. For these reasons, the proposed Project would not result in a significant impact related to the routine transport, use, and disposal of hazardous materials. b) Would the Project create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment?
Less than Significant Impact. As discussed in Section 2.14 Hazardous Waste/Materials, Project construction could expose workers to ADL, ACMs, and LBP.

However, with implementation of PF HM-1.1 through 1.3 and the AMMs described in Section 2.14 Hazardous Waste/Materials, hazardous materials would be properly handled and disposed of during Project construction, resulting in a less than significant impact.
c) Would the Project emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school?
Less than Significant Impact. There are several schools within a quarter-mile of the Project site, including the Oxbow School, located at 530 Third Street, the Children’s Cottage Child Care, located at 1078 East Avenue, and Alta Heights Elementary School, located at 15 Montecito Boulevard. However, as previously discussed, Project operation would not introduce any new uses that would include hazardous emissions or handling of acutely hazardous materials. Project construction would involve the temporary use of gasoline-, diesel- or electric-powered equipment; as well as the use of hazardous materials including petroleum products, lubricants, cleaners, paints, and solvents. Use of these materials would be limited to the Project work limits and the construction staging area. As discussed in Section 2.15 Air Quality, emissions associated with Project construction would not have a significant health risk impact on nearby schools.

Project construction would also potentially disturb surfaces and structures containing hazardous materials such as ACMs, LBP, and ADL. However, with implementation of PF HM 1.1 through 1.3 and AMM HM-1.1 through 1.2, these impacts would be reduced to a less than significant level. For these reasons, the Project would not have a significant hazardous materials impact on schools within a quarter-mile. d) Would the Project be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment? Less than Significant Impact. There are several sites adjacent to the Project limits that are included on the Cortese List. These sites include the Beacon/Texaco gas station, Napa Valley Expo, and Fornasier Property. However, all three of these sites are closed cases and with implementation of PF HM 1.1 through 1.3 and AMM HM-1.1 through -1.2, any residual hazardous materials that may have impacted the soils on-site would be properly handled and disposed of so as to not create a significant hazard to the public or the environment.
e) For a project located within an airport land use plan or, where such a plan has not been adopted, within two nautical miles of a public airport or public use

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airport, would the Project result in a safety hazard or excessive noise for people residing or working in the Project area?
No Impact. The Project alignment is not located within the impact area of the Napa County Airport, the nearest airport to the Project alignment.34 The Project would not include any structures that would require submittal to the FAA for airspace safety review. For these reasons, the Project would not result in a significant airport and aircraft safety hazard impact to the Project area.
f) Would the Project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? Less than Significant Impact. During construction, at least one travel lane in each direction of SR 121 will be kept open during peak hours, as will Third Street, Coombsville Road, and East Avenue. Closures, if necessary, will occur only at night. A TMP would also be prepared in coordination with the local emergency response agencies to ensure that adequate emergency access is provided throughout Project construction. Project operation would improve traffic circulation and safety at the site intersection, resulting in a long-term benefit to emergency response and evacuation. For these reasons, the Project would not impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan. g) Would the Project expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires? No Impact. The Project site is not located in or near state responsibility areas or lands classified as very high fire hazard severity zones. There are areas of local responsibility classified as moderate fire hazard zones along Coombsville Road near the City’s limits, approximately a half-mile east of the Project site.35 The Project would not exacerbate wildfire risk within the moderate fire hazard zone or anywhere else. As previously described, access through the intersection would be maintained throughout construction and potential detours would be scheduled in coordination with NFD as needed. Project operation would result in improved access and safety through the intersection. For these reasons, the Project would not impact evacuation routes or otherwise result in wildfire impacts.

34 Napa County Airport Land Use Commission. Airport Land Use Compatibility Plan. Revised December 1999. Figure 5C Airport Impact Areas.
35 CAL FIRE. City of Napa – Napa County Local Responsibility Area Fire Hazard Severity Zones. Adopted February 24, 2025. https://calfire.app.box.com/file/1785863301140

EXHIBIT A

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3.2.10 Hydrology and Water Quality
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Violate any water quality standards or waste
discharge requirements or otherwise
substantially degrade surface or ground water
quality?

b) Substantially decrease groundwater supplies
or interfere substantially with groundwater
recharge such that the project may impede
sustainable groundwater management of the
basin?

c) Substantially alter the existing drainage
pattern of the site or area, including through the
alteration of the course of a stream or river or
through the addition of impervious surfaces, in a
manner which would:

(i) result in substantial erosion or siltation
on- or off-site;
(ii) substantially increase the rate or amount
of surface runoff in a manner which would
result in flooding on- or offsite;

(iii) create or contribute runoff water which
would exceed the capacity of existing or
planned stormwater drainage systems or
provide substantial additional sources of
polluted runoff; or

(iv) impede or redirect flood flows?
d) In flood hazard, tsunami, or seiche zones,
risk release of pollutants due to project
inundation?
e) Conflict with or obstruct implementation of a
water quality control plan or sustainable
groundwater management plan?

CEQA Significance Determinations for Hydrology and Water Quality a) Would the Project violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality?

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Less than Significant Impact. As discussed in Section 2.11, the Project would comply with the Caltrans NPDES permit, Construction General Permit, and MS4 by implementing BMPs, stormwater treatment controls, and a SWPPP as required by AMM WQ-1.1 through WQ-1.3.
b) Would the Project substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin?
Less than Significant Impact. The Project would result in approximately 0.30 acres of net new impervious surfaces on-site, which would not substantially interfere with groundwater recharge. The Project would not utilize or otherwise deplete existing groundwater supplies. For these reasons, the Project would not impede sustainable groundwater management of the basin.
c) Would the Project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would result in substantial erosion or siltation on- or off-site; substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site; create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff; or impede or redirect flood flows?
Less than Significant Impact. As previously discussed, the Project would result in a net increase in impervious surfaces on-site. However, the project would be required to implement stormwater treatment controls per the requirements of the MS4 permit to prevent substantial erosion, siltation, and stormwater pollution. The Project would not alter the course of the Napa River or any other bodies of water. Therefore, the Project would not result in a significant impact associated with erosion, flooding, or stormwater pollution and would not exceed the capacity of existing or planned stormwater drainage systems.
d) Would the Project risk release of pollutants due to Project inundation in flood hazard, tsunami, or seiche zones?
Less than Significant Impact. The middle portion of the Project site is located in an area with an elevated flood risk equivalent to between a 500-year and 100-year flood risk and the western portion of the Project site is located in a 100-year floodplain. As previously discussed, the risk of pollutants would be temporarily increased during project construction, however, the Project would incorporate BMPs and SWPPP requirements to reduce pollution risk during construction. The Project would also implement LID based stormwater treatment controls, which would also help treat water in a flood event.

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The Project site is not located within a tsunami hazard area36 and is not subject to seiches due to its distance from the shoreline of the San Francisco Bay. For these reasons, the Project would not risk release of pollutants due to inundation in flood hazard, tsunami, or seiche zones.
e) Would the Project conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? Less than Significant Impact. As previously discussed, the Project would be in compliance with the Construction General Permit and MRP. The Project would not utilize or otherwise deplete groundwater resources. Therefore, the Project would not conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan.

3.2.11 Land Use and Planning
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Physically divide an established community?
b) Cause a significant environmental impact due
to a conflict with any land use plan, policy, or
regulation adopted for the purpose of avoiding
or mitigating an environmental effect?

CEQA Significance Determinations for Land Use and Planning a) Would the Project physically divide an established community? Less than Significant Impact. Examples of projects that have the potential to physically divide an established community include new freeways and highways, major arterial streets, and railroad lines. In the Project area, SR 121 currently physically divides the community. While the Project would modify the existing intersection along SR 121, it would not introduce a new highway or other physically divisive feature. The Project would include a new buffered bicycle and pedestrian path throughout the proposed roundabouts and pedestrian crossings that would improve bicycle and pedestrian connectivity in the Project area. For these reasons, the Project would not physically divide an established community.

36 California Department of Conservation. California Tsunami Maps. Accessed February 19, 2025. https://www.conservation.ca.gov/cgs/tsunami/maps

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b) Would the Project cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect?
Less than Significant Impact. The Project would be consistent with the goals and policies of the City’s General Plan, Bicycle Plan, and Pedestrian Plan to make improvements along SR 121, promote increased pedestrian and bicycle connectivity, improve safety, and meet LOS standards.

The Project would require the acquisition of additional right-of-way, as previously described in Table 1.4-1. The right-of-way acquisition would result in some land use changes, including the conversion of one full residential property into roadway facilities.

Other properties would also be partially converted. However, the Project would not introduce any new land uses that would conflict with the surrounding properties that would remain. The Project would not conflict with the City’s land use plans and policies.

3.2.12 Mineral Resources
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Result in the loss of availability of a known
mineral resource that would be a value to the
region and the residents of the state?

b) Result in the loss of availability of a locally
important mineral resource recovery site
delineated on a local general plan, specific plan
or other land use plan?

CEQA Significance Determinations for Mineral Resources
a) Would the Project result in the loss of availability of a known mineral resource that would be a value to the region and the residents of the state? And
b) Would the Project result in the loss of availability of a locally important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan?
No Impact. There are no known mineral resources within the Project site, or the City of Napa.37 Therefore, the Project would not impact mineral resources.

37 City of Napa. General Plan Update Partial Recirculated Draft Environmental Impact Report (SCH# 2021010255) . June 2022.

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3.2.13 Noise
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Generation of a substantial temporary or
permanent increase in ambient noise levels in
the vicinity of the project in excess of standards
established in the local general plan or noise
ordinance, or applicable standards of other
agencies?

b) Generation of excessive groundborne
vibration or groundborne noise levels?
c) For a project located within the vicinity of a
private airstrip or an airport land use plan or,
where such a plan has not been adopted, within
two nautical miles of a public airport or public
use airport, would the project expose people
residing or working in the project area to
excessive noise levels?

CEQA Significance Determinations for Noise
a) Would the Project result in generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies?
Less than Significant Impact. As discussed in Section 2.16 Noise and Vibration, the Project would not result in significant short-term or long-term noise impacts. The Project would additionally be required to incorporate AMM NOI-1.1 through NOI-1.6 per Caltrans’ Standard Specifications, which would further reduce construction noise impacts.
b) Would the Project result in generation of excessive groundborne vibration or groundborne noise levels?
Less than Significant Impact with Mitigation Incorporated. As discussed in Section

2.16 Noise and Vibration, Project construction would result in vibration levels that could cause damage to existing buildings. However, with incorporation of MM NOI-2.1 through NOI-2.3, potential impacts to adjacent buildings would be reduced to a less than significant level.
c) For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two nautical miles of a

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public airport or public use airport, would the Project expose people residing or working in the project area to excessive noise levels?
No Impact. The Napa County Airport, the nearest airport to the Project site, is located approximately five miles south of the Project limits. Additionally, the proposed roundabouts Project would not introduce any new residences or workplaces to the site.

The Project would not expose people residing or working in the area to excessive airport noise levels.

3.2.14 Population and Housing
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Induce substantial unplanned population
growth in an area, either directly (for example,
by proposing new homes and businesses) or
indirectly (for example, through extension of
roads or other infrastructure)?

b) Displace substantial numbers of existing
people or housing, necessitating the
construction of replacement housing
elsewhere?

CEQA Significance Determinations for Population and Housing a) Would the Project induce substantial unplanned population growth in an area, either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)? Less than Significant Impact. The proposed intersection improvements would not directly induce population growth by proposing new homes or businesses. The Project would improve vehicle congestion and safety features of the existing intersection, which could make the area more attractive for development to an extent. However, the Project would not extend the existing roadway or otherwise drive growth in unplanned areas or areas where growth is not currently foreseeable. For these reasons, the Project would not result in substantial unplanned growth.
b) Would the Project displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere? Less than Significant Impact. The Project would require a full right-of-way acquisition of one residential property. Assuming the City’s average of 2.50 persons per household,38 the Project would conservatively displace two residents. In comparison

38 California Department of Finance. “E-5 Population and Housing Estimates for Cities, Counties, and the State, January 2021-2024, with 2020 Benchmark.” Accessed: February 19, 2025. Available at:

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with the City’s population of 77,174 persons, this would not be a substantial displacement of existing people or housing. The Project would not directly necessitate the construction of replacement housing elsewhere, as the displaced people would likely be able to find available housing within the City’s 31,994 existing housing units.39

3.2.15 Public Services
a) Would the project result in substantial
adverse physical impacts associated with the
provision of new or physically altered
governmental facilities, need for new or
physically altered governmental facilities, the
construction of which could cause significant
environmental impacts, in order to maintain
acceptable service ratios, response times or
other performance objectives for any of the
public services:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
Fire protection?
Police protection?
Schools?
Parks?
Other public facilities?
CEQA Significance Determinations for Public Services
No Impact. The proposed intersection improvements are not a land use project (e.g., residential, commercial, industrial, etc.) and would not directly introduce new residents or workers to the Project area. The Project would make improvements to an existing intersection and, as aforementioned, would not result in any new residents or workers in the area that would increase demand upon local public services, particularly fire protection services, police services, schools, parks, or libraries. Therefore, no new or physically altered governmental facilities would be needed to accommodate the project.

During construction, at least one travel lane in each direction of SR 121 will be kept open during peak hours, as will Third Street, Coombsville Road, and East Avenue.

Closures, if necessary, will occur only at night. A TDM would also be prepared in coordination with the NFD and NPD to ensure that adequate emergency access is provided throughout Project construction. Project operation would improve traffic circulation and safety at the site intersection, resulting in a long-term benefit to fire and police response times. For these reasons, the Project would not result in significant

https://dof.ca.gov/forecasting/demographics/estimates/e-5-population-and-housing-estimates-for-cities- counties-and-the-state-2020-2024/
39 Ibid.

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environmental impacts associated with the construction of new or physically altered governmental facilities.

3.2.16 Recreation
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Would the project increase the use of existing
neighborhood and regional parks or other
recreational facilities such that substantial
physical deterioration of the facility would occur
or be accelerated?

b) Does the project include recreational facilities
or require the construction or expansion of
recreational facilities which might have an
adverse physical effect on the environment?

CEQA Significance Determinations for Recreation
a) Would the Project increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated?
No Impact. The Project proposes intersection improvements and is not a land use project (e.g., residential, commercial, industrial, etc.). As previously discussed, the Project would make improvements to an existing intersection and would not introduce any new residents or workers to the area who would increase demand upon existing parks or other recreational facilities.
b) Does the Project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment?
No Impact. The Project does not include any recreational facilities and as noted above, would not require the construction or expansion of existing recreational facilities.

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3.2.17 Transportation
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Conflict with a program, plan, ordinance, or
policy addressing the circulation system,
including transit, roadway, bicycle and
pedestrian facilities?

b) Would the project conflict or be inconsistent
with CEQA Guidelines section 15064.3,
subdivision (b)?

c) Substantially increase hazards due to a
geometric design feature (e.g., sharp curves or
dangerous intersections) or incompatible uses
(e.g., farm equipment)?

d) Result in inadequate emergency access?
CEQA Significance Determinations for Transportation
a) Would the Project conflict with a program, plan, ordinance, or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities?
Less than Significant Impact. The Project is listed in, and therefore consistent with, MTC’s Plan Bay Area 2050, which is the RTP.40 The Project is also included in the adopted 2025 TIP for the San Francisco Bay Area.41 The No Build Alternative would not be consistent with the RTP and TIP.

The Project would also be consistent with City of Napa General Plan policies TE 3-3, TE 3-5, and TE 5-1 and the City’s Bicycle and Pedestrian Master Plans because it would improve bicycle and pedestrian facility connections and intersection safety and accessibility. The No Build Alternative would not be consistent with the Bicycle Master Plan, Pedestrian Master Plan, or the General Plan’s policies that relate to bicycle and pedestrian facility improvements. For these reasons, the Project would not conflict with a program, plan, ordinance, or policy addressing the circulation system. b) Would the Project conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b)?
Less than Significant Impact. Historically, transportation analyses prepared under CEQA have utilized delay and congestion on the roadway system as the primary metric

40 RTP Project ID 21-T07-056
41 TIP Project ID NAP170009

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for the identification of traffic impacts and potential roadway improvements to relieve traffic congestion that may result due to a proposed project. However, the State of California has recognized the limitations of measuring and mitigating only vehicle delay at intersections. Therefore, in 2013, SB 743 became law, which requires jurisdictions to stop using congestion and delay metrics, such as level of service (LOS), as the measurement for CEQA impacts in a transportation analysis. Per SB 743, by July 2020, all public agencies were required to base the determination of transportation impacts under CEQA on VMT rather than LOS. Section 15064.3(b)(2) of the CEQA Guidelines states that transportation projects that reduce, or have no impact on, VMT should be presumed to cause a less than significant transportation impact.

The City of Napa’s adopted VMT thresholds of significance do not include a threshold for transportation improvements projects such as the proposed intersection improvements. Therefore, this discussion is based on Caltrans’ Transportation Analysis Under CEQA (2020) guidelines. Section 5.1.1 of Transportation Analysis Under CEQA establishes screening criteria for non-capacity increasing projects. Projects that fit these criteria may be assumed to have a less than significant VMT impact. The following screening criteria are applicable to the proposed project:
• Installation of roundabouts or traffic circles
• Addition of new or enhanced bike or pedestrian facilities on existing streets/highways or within existing public right-of-way • Addition of Class I bike paths, trails, multi-use paths, or other off-road facilities that serve non-motorized travel
The proposed intersection improvements Project would not increase roadway capacity and is exempt from further VMT evaluation per Caltrans’ screening criteria. For these reasons, the Project would not result in a significant VMT impact and would not conflict or be inconsistent with CEQA Guidelines Section 15064.3 (b). c) Would the Project substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)?
Less than Significant Impact. The proposed roundabouts have been designed to improve safety and reduce the collisions at the Project intersection. The Project would be required to comply with current highway design standards. The Project would not increase hazards due to a geometric design feature or incompatible uses. d) Would the Project result in inadequate emergency access? Less than Significant Impact. The Project would not sever or adversely impact existing emergency response routes through the Project intersection. During the construction phase of the project, any temporary lane or road closures and detours would be coordinated in advance with the NFD, as well as with other emergency responders (e.g., police, ambulance, etc.). Upon completion of the Project, emergency access through the Project intersection would be improved.

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3.2.18 Tribal Cultural Resources
Would the project cause a substantial adverse
change in the significance of a tribal cultural
resource, defined in Public Resources Code
section 21074 as either a site, feature, place,
cultural landscape that is geographically defined
in terms of the size and scope of the landscape,
sacred place, or object with cultural value to a
California Native American tribe, and that is:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Listed or eligible for listing in the California
Register of Historical Resources, or in a local
register of historical resources as defined in
Public Resources Code section 5020.1(k), or

b) A resource determined by the lead agency, in
its discretion and supported by substantial
evidence, to be significant pursuant to criteria
set forth in subdivision (c) of Public Resources
Code Section 5024.1. In applying the criteria set
forth in subdivision (c) of Public Resource Code
Section 5024.1, the lead agency shall consider
the significance of the resource to a California
Native American tribe.

CEQA Significance Determinations for Tribal Cultural Resources a) Would the Project cause a substantial adverse change in the significance of a tribal cultural resources that is listed or eligible for listing in the California Register of Historical Resources, or in a local register of historical resources as defined in Public Resources Code section 5020.1(k)?
And
b) Would the Project cause a substantial adverse change in the significance of a tribal cultural resource that is determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Public Resources Code Section 5024.1. In applying the criteria set forth in subdivision (c) of Public Resource Code Section 5024.1, the lead agency shall consider the significance of the resource to a California Native American tribe?
Less than Significant Impact. A search of the NAHC sacred lands file was conducted.

The results were positive, indicating the potential presence of sacred lands, and NAHC provided a list of recommended tribes to consult for further information. Consultation letters were sent on August 7, 2024, by US Mail and email to 16 individuals representing eight tribal organizations. Follow-up emails were sent on September 3, 2024 to non-responsive tribes. The Muwekma Ohlone Tribe of the SF Bay Area, Mishewal-Wappo Tribe of Alexander Valley, and Yocha Dehe Wintun Nation provided responses. A tribal representative of the Muwekhma Ohlone Tribe stated that the tribe

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declined consultation because the Project area is outside of the tribe’s jurisdiction.

Based on their requests, Caltrans and the City of Napa met with the Mishewal-Wappo Tribe of Alexander Valley on December 9, 2024, and Yocha Dehe Wintun Nation on December 16, 2024 to discuss the Project. During the consultation meetings, both tribes noted that the Project area is sensitive for tribal cultural resources (TCRs) and requested that avoidance, minimization, and mitigation measures be implemented to avoid impacts to buried TCRs. Consultation with both tribes is ongoing.

With implementation of AMM TCR-1.1 and 1.2, impacts to buried TCRs would be reduced to a less than significant level, if encountered during ground-disturbing construction activities.

AMM TCR-1.1: Prior to the initiation of construction, an agency approved archaeologist and Native American representative will prepare and conduct an educational program to instruct construction workers of the obligation to protect and preserve valuable resources. This program shall be provided to all construction workers as a field training prior to the beginning of ground-disturbing activities, and shall at minimum, the training will include a discussion of archaeological and tribal resources that may be encountered (including the traditional importance of resources such as cultural landscapes, significant waterways, and ethnobotanical plants); the procedures when working in Tribal Monitoring Areas or near Environmentally Sensitive Areas, if applicable; a summary of state and federal laws and penalties under the laws; samples or visual aids of resources that could be encountered in the project vicinity; instructions regarding the need to halt work in the vicinity of any potential archaeological and Native American resources encountered; and measures to notify their supervisor, City of Napa Public Works Director, and District 4 Office of Cultural Resources Studies.

AMM TCR-1.2: Construction related activities (including, but not limited to, demolition/ excavation, grading, and utility trenching) shall be monitored by a Native American tribal monitor to be retained by Caltrans. The tribal monitor shall have authority to halt construction activities temporarily in the immediate vicinity of an unanticipated find until its significance can be assessed by the tribal monitor.

Monitoring within the Tribal Monitoring Area may move to a part-time or intermittent schedule by mutual agreement between the Tribes, the City of Napa and Caltrans District 4 Office of Cultural Resources Studies.

A summary report of the monitoring results, including any protective measures implemented, shall be submitted to Caltrans upon completion of the construction monitoring.

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3.2.19 Utilities and Service Systems
Would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Require or result in the relocation or
construction of new or expanded water,
wastewater treatment or storm water drainage,
electric power, natural gas, or
telecommunications facilities, the construction
or relocation of which could cause significant
environmental effects?

b) Have sufficient water supplies available to
serve the project and reasonably foreseeable
future development during normal, dry and
multiple dry years?

c) Result in a determination by the wastewater
treatment provider which serves or may serve
the project that it has adequate capacity to
serve the project’s projected demand in addition
to the provider’s existing commitments?

d) Generate solid waste in excess of State or
local standards, or in excess of the capacity of
local infrastructure, or otherwise impair the
attainment of solid waste reduction goals??

e) Comply with federal, state, and local
management and reduction statutes and
regulations related to solid waste?

CEQA Significance Determinations for Utilities and Service Systems a) Would the Project require or result in the relocation or construction of new or expanded water, wastewater treatment or stormwater drainage, electric power, natural gas, or telecommunications facilities, the construction or relocation of which could cause significant environmental effects?
Less than Significant Impact. The proposed roundabouts would not result in an increase in demand for utilities that would require new or expanded facilities. Due to the significant grading that will be required to construct the new roundabouts, relocation of the water line that runs from Third Street as well as six joint utility poles may need to be relocated or undergrounded. In addition, adjustment of utility vaults to match the final pavement surface elevation would be required along SR 121. All other existing utilities would be protected in place. Utility relocations and adjustments would occur within the existing City right-of-way. The proposed utility relocations and adjustments would be relatively minor and would be subject to the construction-related AMMs described

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throughout this Final EIR/EA (see Section 2.9 Cultural Resources, Section 2.11 Water Quality and Stormwater Runoff, Section, Section 2.14 Hazardous Waste/Materials, Section 2.15 Air Quality, and Section 2.16 Noise and Vibration). Therefore, with implementation of the construction-related AMMs previously described throughout this Final EIR/EA, the Project would not result in a significant environmental effect associated with the proposed utility relocations and adjustments. b) Would the Project have sufficient water supplies available to serve the project and reasonably foreseeable future development during normal, dry and multiple dry years?
And
c) Would the Project result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments? And
d) Would the Project generate solid waste in excess of State or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals?
And
e) Would the Project comply with federal, state, and local management and reduction statutes and regulations related to solid waste? Less than Significant Impact. The Project would include landscape irrigation, however, water used for Project landscaping would be minor compared with the existing water supplies. The Project would not generate wastewater. The Project would not generate solid waste during the operational phase. Solid waste generated from the demolition of the existing roadway would be recycled in accordance with the City’s Construction and Demolition Debris Recycling Ordinance.

3.2.20 Wildfire
If located in or near state responsibility areas or
lands classified as very high fire hazard severity
zones, would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Substantially impair an adopted emergency
response plan or emergency evacuation plan?
b) Due to slope, prevailing winds, and other
factors, exacerbate wildfire risks, and thereby
expose project occupants to, pollutant

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If located in or near state responsibility areas or
lands classified as very high fire hazard severity
zones, would the project:

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
concentrations from a wildfire or the
uncontrolled spread of a wildfire?
c) Require the installation or maintenance of
associated infrastructure (such as roads, fuel
breaks, emergency water sources, power lines
or other utilities) that may exacerbate fire risk or
that may result in temporary or ongoing impacts
to the environment?

d) Expose people or structures to significant
risks, including downslope or downstream
flooding or landslides, as a result of runoff, post-
fire slope instability, or drainage changes?

CEQA Significance Determinations for Wildfire
No Impact. The Project site is not located in or near state responsibility areas or lands classified as very high fire hazard severity zones. There are areas of local responsibility classified as moderate fire hazard zones along Coombsville Road near the City’s limits, approximately a half-mile east of the Project site.42 The Project would not exacerbate wildfire risk within the moderate fire hazard zone or anywhere else. As previously described, access through intersection would be maintained throughout construction and potential detours would be scheduled in coordination with NFD as needed. Project operation would result in improved access and safety through the intersection. For these reasons, the Project would not impact evacuation routes or otherwise result in wildfire impacts.

3.2.21 Mandatory Findings of Significance

Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
a) Does the project have the potential to
substantially degrade the quality of the
environment, substantially reduce the habitat of
a fish or wildlife species, cause a fish or wildlife
population to drop below self-sustaining levels,
threaten to eliminate a plant or animal

42 CAL FIRE. City of Napa – Napa County Local Responsibility Area Fire Hazard Severity Zones. Adopted February 24, 2025. https://calfire.app.box.com/file/1785863301140

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Significant
and
Unavoidable
Impact
Less Than
Significant
with
Mitigation
Incorporated
Less Than
Significant
Impact
No
Impact
community, substantially reduce the number or
restrict the range of a rare or endangered plant
or animal or eliminate important examples of the
major periods of California history or prehistory?
b) Does the project have impacts that are
individually limited, but cumulatively
considerable? ("Cumulatively considerable"
means that the incremental effects of a project
are considerable when viewed in connection
with the effects of past projects, the effects of
other current projects, and the effects of
probable future projects)?

c) Does the project have environmental effects
which will cause substantial adverse effects on
human beings, either directly or indirectly?

CEQA Significance Determinations for Mandatory Findings of Significance a) Does the Project have the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? Significant and Unavoidable Impact. As previously described in Section 2.18 Natural Communities, 2.19 Animal Species, and 2.20 Threatened and Endangered Species, the Project has the potential to impact special-status wildlife species and some riparian habitat adjacent to the proposed construction staging area during Project construction.

However, with implementation of the AMMs described in these sections and PF BIO-

1.1, impacts to these species and riparian habitat would be less than significant.

As discussed in Section 2.9 Cultural Resources, the Project would have a less than significant impact on potential buried archaeological resources with implementation of PF CULT-1.1 and 1.2. However, the Project would demolish the existing building at 801 Silverado Trail, a designated historic resource. The Project would implement MM CULT-

1.1 to document the resource proposed for demolition, but the Project’s impact cannot be mitigated to a less than significant level.
b) Does the Project have impacts that are individually limited, but cumulatively considerable? ("Cumulatively considerable" means that the incremental effects of a project are considerable when viewed in connection with the effects of past

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projects, the effects of other current projects, and the effects of probable future projects)?
Less than Significant Impact with Mitigation Incorporated.

In a cumulative impacts analysis, the identification of “past, present, and reasonably foreseeable future actions” can utilize either the “list approach” or the “adopted plan” approach. The list approach identifies specific projects in the vicinity, typically provided by a local planning department. The adopted plan approach relies on a general plan or transportation plan or other planning document, which by definition accounts for cumulative growth in a defined area.

For this analysis, both the list and adopted plan approach are utilized as there are multiple projects proposed in the Project vicinity (see Table 3.2-1) and impacts from future growth projected by the City of Napa 2040 General Plan were considered. As an example, the traffic model that was used to project future build and no-build conditions is based on the planned growth of the area. The traffic projections from cumulative growth were also used in the quantification of air quality and noise impacts.

The discussion, below, addresses resource areas where the Project will result in an impact and, therefore, there is potential for a cumulative impact. Resource areas not affected by the Project are not discussed because, by definition, no cumulative impact could occur. Examples of the latter include the topics listed in Section 2.1 Topics Considered but Determined Not to be Relevant.

Table 3.2-1: Cumulative Projects List
Name and Location Description Distance to
Project Site Status
SR 121/Hennessey
Drive Intersection
Improvements
Install signals/roundabout at the
intersection of SR 121 and
Hennessey
250 feet Pending
Le Petit Elephant Use
Permit (15 Chapel Hill
Drive)
A use permit authorizing a daycare
for up to 250 children, youth
services, and reduced parking.

0.3 miles Approved
Coombsville Road
(Pascale Pl to City
Limits)
Roadway rehabilitation including
pavement and striping work,
possible concrete and storm drain
improvements, and “complete
streets” elements.

0.4 miles Programmed
Soscol Square
Shopping Center (333
and 407 Soscol
Avenue)
Redevelop the vacant site with a
new retail center including a 55,000
square-foot retail building, a 9,800
square-foot commercial building,
and a 4,970 square foot fast food
restaurant with a double lane drive-
through.

0.7 miles Approved

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Name and Location Description Distance to
Project Site Status
SR 121 Tulucay Creek
Bridge Replacement
Replace the existing two-span, 45-
foot-long, concrete Tulucay Creek
Bridge with a single-span, concrete
box bridge

0.7 miles Approved
The Grange
Campground (western
side of SR 121,
between Stonecrest
Drive and Hagen Road)
Construct a campground with up to
five permanent buildings, 100 fixed
recreational lodging units, a
recreational activity space, and a
pervious parking area.

1.2 miles Pending

The Project’s effects on certain resource areas such as Visual/Aesthetics, Geology/Soils/Seismic/Topography, Hazardous Waste/Materials, Noise and Vibration, and the biological environment would be limited to the Project limits and adjacent parcels. The SR 121/Hennessey Drive Intersection Improvements project is adjacent to the south of the Project limits and could have impacts on overlapping parcels with the proposed Project. The other projects listed in Table 3.2-1 would not impact parcels adjacent to the Project site and thus, would not have the potential to contribute toward a significant cumulative impact to these resources.

The SR 121/Hennessey Drive Intersection Improvements project would largely not change the existing visual character of the vicinity as it would largely be limited to roadway improvements and the proposed signal poles would not obstruct a scenic vista or scenic resource. The SR 121/Hennessey Drive project would similarly be located in an urban area of the City of Napa that does not provide suitable habitat for special- status plant and wildlife species. The project may similarly result in tree removal and would also be required to implement mitigation measures and standard conditions to ensure compliance with the MBTA and the City of Napa’s tree programs. The SR 121/Hennessey Drive project would be located farther from the Napa River and would not have the potential to contribute toward a cumulative impact on riparian habitat, WPT turtle, or special-status fish species. The SR 121/Hennessey Drive Intersection Improvements project would be subject to similar geologic conditions as the proposed Project and would also be required to conduct a site-specific geotechnical investigation and incorporate design measures to reduce the potential for structural failure due to geologic hazards. The SR 121/Hennessey Drive would also have the potential to encounter ADL, ACMs, and LBP during construction and would similarly be required to implement mitigation to ensure the safe handling and disposal of hazardous materials.

For these reasons, the Project would not result in a significant cumulative impact on these resource areas.

Construction noise and vibration would be temporary and would be kept to a less than significant level with implementation of the AMMs and MMs described in Section 2.16 Noise and Vibration. It is possible that some of the Project construction activities may occur at the same time as the SR 121/Hennessey Drive project. However, it is unlikely that the excavation and grading phases, which are typically the most noise-generating

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phases of construction, would occur at the same time because the SR 121/Henessey Drive project is still in the project initiation document (PID) phase at the time of preparing this Final EIR/EA and thus, will likely take longer to reach project approval than the proposed Project. Additionally, the SR 121/Hennessey Drive Intersection Improvement project, and any other nearby projects, would be required to implement similar construction noise BMPs. For these reasons, the Project would not make a substantial contribution to a significant cumulative noise impact. Neither the SR 121/Hennessey Drive project nor the proposed Project would result in an increase in vehicle traffic or otherwise result in a substantial permanent noise increase. The other projects listed in Table 3.2-1 are farther away and would not impact the same noise sensitive receptors as the proposed Project to result in a cumulatively considered noise impact.

Human Environment
The Project would have minimal, indirect impacts on growth, utilities and emergency services, and traffic. The Project’s impacts on these resources would not be a considerable contribution toward a cumulative impact when compared to the development projects in the area that are adding new commercial and recreation land uses which will directly result in growth, an increased demand in utilities and emergency services, and traffic. The Project would demolish one residential property, which would not represent a considerable contribution toward a cumulative impact on relocations and real property acquisition. The Project would have temporary construction impacts on the local community, which could include cumulative noise, air quality, and hazardous materials impacts. As described further in this section, such impacts are not anticipated to be significant. Operationally, the Project would benefit the surrounding communities and thus, would not contribute to a permanent cumulative impact.

All the cumulative projects listed in Table 3.2-1 would be required to implement similar AMMs as the proposed Project to halt construction in the event of discovering an archaeological resource on-site and implement the proper inspection and handling of the resource. Therefore, a significant cumulative impact on archaeological resources would be avoided. It is not anticipated that any of the cumulative projects would demolish properties that contribute to the East Napa Historic District and thus, would not result in a cumulative impact on historic resources.

Physical Environment
All the cumulative projects listed in Table 3.2-1 would be subject to similar hydrological conditions as the proposed Project. All the cumulative projects would also be subject to the NPDES and MS4 permit (including preparation of a SWPPP if disturbance is greater than one acre). For these reasons, the cumulative impact of the Project combined with other cumulative projects would not result in a significant cumulative hydrology or water quality impact.

Because air pollutant and GHG emissions would contribute to regional and global emissions of such pollutants, the identified thresholds developed by the Air District and used by the City of Napa were developed such that a project-level impact would also be a cumulatively considerable impact. The Project would not result in significant emissions

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of air pollutants or GHG emissions and, therefore, would not make a substantial contribution to air quality or GHG emissions impacts.

The Project would have a minimal impact on operational energy consumption and thus, would not make a considerable contribution toward a permanent cumulative energy impact. All the projects in Table 3.2-1 would involve temporary energy consumption during construction, however, construction processes are generally designed to be efficient in order to avoid excess monetary costs. That is, equipment and fuel are not typically used wastefully because of the added expense associated with renting the equipment, maintaining it, and fueling it. For these reasons, the cumulative energy used during construction of the proposed Project and the nearby projects would not be used wastefully or inefficiently.
c) Does the Project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? Less than Significant Impact with Mitigation Incorporated. The Project’s direct potential impacts on the human environment are discussed in Sections 2.2 through 2.9 and were determined to be less than significant. The Project would also have the potential to cause adverse effects on human beings during the construction phase via release of hazardous materials, air pollutant emissions, and noise. As described in Sections 2.14 Hazardous Waste/Materials, 2.15 Air Quality, and 2.16 Noise and Vibration, these impacts would be reduced to a less than significant impact with incorporation of the AMMs and MMs described in their respective sections of this Final EIR/EA.

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3.3 CLIMATE CHANGE
Climate change refers to long-term changes in temperature, precipitation, wind patterns, and other elements of the Earth's climate system. The Intergovernmental Panel on Climate Change, established by the United Nations and World Meteorological Organization in 1988, is devoted to greenhouse gas (GHG) emissions reduction and climate change research and policy. Climate change in the past has generally occurred gradually over millennia, or more suddenly in response to cataclysmic natural disruptions. The research of the Intergovernmental Panel on Climate Change and other scientists over recent decades, however, has unequivocally attributed an accelerated rate of climatological changes over the past 150 years to GHG emissions generated from the production and use of fossil fuels.

Human activities generate GHGs consisting primarily of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), tetrafluoromethane, hexafluoroethane, sulfur hexafluoride (SF6), and various hydrofluorocarbons (HFCs). CO2 is the most abundant GHG; while it is a naturally occurring and necessary component of Earth’s atmosphere, fossil-fuel combustion is the main source of additional, human-generated CO2 that is the main driver of climate change. In the U.S. and in California, transportation is the largest source of GHG emissions, mostly CO2.

The impacts of climate change are already being observed in the form of sea level rise, drought, extended and severe fire seasons, and historic flooding from changing storm patterns. The most important strategy to address climate change is to reduce GHG emissions. Additional strategies are necessary to mitigate and adapt to these impacts.

In the context of climate change, “mitigation” involves actions to reduce GHG emissions to lessen adverse impacts that are likely to occur. “Adaptation” is planning for and responding to impacts to reduce vulnerability to harm, such as by adjusting transportation design standards to withstand more intense storms, heat, and higher sea levels. This analysis will include a discussion of both in the context of this transportation Project.

3.3.1 Regulatory Setting
For a full list of laws, regulations, and guidance related to climate change (GHGs and adaptation), please refer to Caltrans’ Standard Environmental Reference (SER), Chapter 16, Climate Change.

3.3.1.1 Federal
To date, no nationwide numeric mobile-source GHG reduction targets have been established; however, federal agencies are mandated to consider the effects of climate change in their environmental reviews.

The National Environmental Policy Act (NEPA) (42 United States Code [USC] Part 4332) is the basic national charter for protection of the environment which establishes policy, sets goals, and provides direction for carrying out the policy. NEPA requires

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federal agencies to assess the environmental effects of their proposed actions prior to making a decision on the action or project.

Early efforts by the federal government to improve fuel economy and energy efficiency to address climate change and its associated effects include The Energy Policy and Conservation Act of 1975 (42 USC Section 6201); and Corporate Average Fuel Economy (CAFE) Standards. The U.S. Department of Transportation’s National Highway Traffic and Safety Administration (NHTSA) sets and enforces corporate average fuel economy (CAFÉ) standards for on-road motor vehicles sold in the United States. The Environmental Protection Agency (U.S. EPA) calculates average fuel economy levels for manufacturers, and also sets related GHG emissions standards for vehicles under the Clean Air Act. Raising CAFE standards leads automakers to create a more fuel-efficient fleet, which improves our nation’s energy security, saves consumers money at the pump, and reduces GHG emissions (U.S. DOT 2014). These standards are periodically updated and published through the federal rulemaking process.

3.3.1.2 State
California has been innovative and proactive in addressing GHG emissions and climate change by passing multiple Senate and Assembly bills and executive orders (EOs).

In 2005, EO S-3-05 initially set a goal to reduce California’s GHG emissions to 80 percent below year 1990 levels by 2050, with interim reduction targets. Later EOs and Assembly and Senate bills refined interim targets and codified the emissions reduction goals and strategies. The California Air Resources Board (ARB) was directed to create a climate change scoping plan and implement rules to achieve “real, quantifiable, cost- effective reductions of greenhouse gases.” Ongoing GHG emissions reduction was also mandated in Health and Safety Code (H&SC) Section 38551(b). In 2022, the California Climate Crisis Act was passed, establishing state policy to reduce statewide human- caused GHG emissions by 85 percent below 1990 levels, achieve net zero GHG emissions by 2045, and achieve and maintain negative emissions thereafter.

Beyond GHG reduction, the State maintains a climate adaptation strategy to address the full range of climate change stressors, and passed legislation requiring state agencies to consider protection and management of natural and working lands as an important strategy in meeting the state’s GHG reduction goals.

3.3.2 Environmental Setting
The proposed Project is in an urban area of the City of Napa with a well-developed road and street network. Existing land uses in the Project area consist of residential, commercial, light industrial, a school, a cemetery, and the Napa Valley Expo. SR 121 is heavily used during peak hours in the Project area. The RTP, Plan Bay Area 2050, prepared by MTC guides transportation and housing development in the Project area.

The City of Napa General Plan Climate Change and Sustainability Element addresses GHGs in the Project area.

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3.3.2.1 GHG Inventories
A GHG emissions inventory estimates the amount of GHGs discharged into the atmosphere by specific sources over a period of time. Tracking annual GHG emissions allows countries, states, and smaller jurisdictions to understand how emissions are changing and what actions may be needed to attain emission reduction goals. U.S. EPA is responsible for documenting GHG emissions nationwide, and the ARB does so for the state of California, as required by H&SC Section 39607.4. Cities and other local jurisdictions may also conduct local GHG inventories to inform their GHG reduction or climate action plans.

National GHG Inventory
The annual GHG inventory submitted by the U.S. EPA to the United Nations provides a comprehensive accounting of all human-produced sources of GHGs in the United States. Total national GHG emissions from all sectors in 2022 were 5,489.0 million metric tons (MMT), factoring in deductions for carbon sequestration in the land sector. (Land Use, Land Use Change, and Forestry provide a carbon sink equivalent to 15% of total U.S. emissions in 2022 [U.S. EPA 2024a].) While total GHG emissions in 2022 were 17% below 2005 levels, they increased by 1% over 2021 levels. Of these, 80% were CO2, 11% were CH4, and 6% were N2O; the balance consisted of fluorinated gases. From 1990 to 2022, CO2 emissions decreased by only 2% (U.S. EPA 2024a).

The transportation sector’s share of total GHG emissions remained at 28% in 2022 and continues to be the largest contributing sector (Figure 3.3-1). Transportation activities accounted for 37% of U.S. CO2 emissions from fossil fuel combustion in 2022. This is a decrease of 0.5% from 2021 (U.S. EPA 2024a, 2024b)).

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Figure 3.3-1: U.S. 2022 Greenhouse Gas Emissions

(Source: U.S. EPA 2024b)
State GHG Inventory
ARB collects GHG emissions data for transportation, electricity, commercial/residential, industrial, agricultural, and waste management sectors each year. It then summarizes and highlights major annual changes and trends to demonstrate the state’s progress in meeting its GHG reduction goals. Overall statewide GHG emissions declined from 2000 to 2021 despite growth in population and state economic output (Figure 3.3-3) Transportation emissions remain the largest contributor to GHG emissions in the state (Figure 3.3-2) (ARB 2023).

Figure 3.3-2: California 2021 Greenhouse Gas Emissions by Economic Sector

(Source: ARB 2023)

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Figure 3.3-3: Change in California GDP, Population, and GHG Emissions since 2000

(Source: ARB 2023)

AB 32 required ARB to develop a Scoping Plan that describes the approach California will take to achieve the goal of reducing GHG emissions to 1990 levels by 2020, and to update it every 5 years. The AB 32 Scoping Plan and the subsequent updates contain the main strategies California will use to reduce GHG emissions. ARB adopted the first scoping plan in 2008. The second updated plan, California’s 2017 Climate Change Scoping Plan, adopted on December 14, 2017, reflects the 2030 target established in EO B-30-15 and SB 32. The 2022 Scoping Plan for Achieving Carbon Neutrality, adopted September 2022, assesses progress toward the statutory 2030 reduction goal and defines a path to reduce human-caused emissions to 85 percent below 1990 levels and achieve carbon neutrality no later than 2045, in accordance with AB 1279 (ARB 2022a).

3.3.2.2 Regional Plans
As required by The Sustainable Communities and Climate Protection Act of 2008, ARB sets regional GHG reduction targets for California’s 18 metropolitan planning organizations (MPOs) to achieve through planning future projects that will cumulatively achieve those goals, and reporting how they will be met in the Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS). Targets are set at a percent reduction of passenger vehicle GHG emissions per person from 2005 levels. The proposed project is included in the RTP/SCS for MTC. The regional reduction target for [MPO] is 19 percent by 2035 (ARB 2021).

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The Regional GHG reduction plan is MTC’s Plan Bay Area 2050. The City of Napa has not adopted a GHG Reduction Strategy or Climate Action Plan. Some of the key policies of Plan Bay Area 2050 are listed below:
• Policy T8: Build a complete streets network
• Policy T10: Enhance local transit frequency, capacity, and reliability • Policy T11: Expand and modernize the regional rail network • Policy EN1: Adapt to sea level rise
• Policy EN7: Expand commute trip reduction programs at major employers • Policy EN8: Expand clean vehicle initiatives
• Policy EN9: Expand transportation demand management initiatives

3.3.3 Project Analysis
GHG emissions from transportation projects can be divided into those produced during operation and use of the State Highway System (SHS) (operational emissions) and those produced during construction. The primary GHGs produced by the transportation sector are CO2, CH4, N2O, and HFCs. CO2 emissions are a product of burning gasoline or diesel fuel in internal combustion engines, along with relatively small amounts of CH4 and N2O. A small amount of HFC emissions related to refrigeration is also included in the transportation sector. (GHGs differ in how much heat each traps in the atmosphere, called global warming potential, or GWP. CO2 is the most important GHG, so amounts of other gases are expressed relative to CO2, using a metric called “carbon dioxide equivalent”, or CO2e. The global warming potential of CO2 is assigned a value of 1, and the GWP of other gases is assessed as multiples of CO2.) The CEQA Guidelines generally address greenhouse gas emissions as a cumulative impact due to the global nature of climate change (Pub. Resources Code, § 21083(b)(2)). As the California Supreme Court explained, “because of the global scale of climate change, any one project's contribution is unlikely to be significant by itself.” (Cleveland National Forest Foundation v. San Diego Assn. of Governments (2017) 3 Cal.5th 497, 512.) In assessing cumulative impacts, it must be determined if a project’s incremental effect is “cumulatively considerable” (CEQA Guidelines Sections 15064(h)(1) and 15130).

To make this determination, the incremental impacts of the project must be compared with the effects of past, current, and probable future projects. Although climate change is ultimately a cumulative impact, not every individual project that emits greenhouse gases must necessarily be found to contribute to a significant cumulative impact on the environment.

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3.3.3.1 Operational Emissions
The purpose of the proposed Project is to reduce vehicle delay and congestion and improve safety for all users of the intersection, including bicycles and pedestrians. The Project would therefore not increase the vehicle capacity of the roadway. This type of project generally causes minimal or no increase in operational GHG emissions.

Because the project would not increase the number of travel lanes on SR 121 or any of the local roadways, no increase in vehicle miles traveled (VMT) would occur. While some GHG emissions during the construction period would be unavoidable, no increase in operational GHG emissions is expected.

3.3.3.2 Construction Emissions
Construction GHG emissions would result from material processing and transportation, on-site construction equipment, and traffic delays due to construction. These emissions will be produced at different levels throughout the construction phase; their frequency and occurrence can be reduced through innovations in plans and specifications and by implementing better traffic management during construction phases. While construction GHG emissions are only produced for a short time, they have long-term effects in the atmosphere, so cannot be considered “temporary” in the same way as criteria pollutants that subside after construction is completed.

Use of long-life pavement, improved traffic management plans, and changes in materials can also help offset GHG emissions produced during construction by allowing longer intervals between maintenance and rehabilitation activities.

Construction emissions were estimated using the latest version of Caltrans’ Cal- CET2021 emissions model. As shown in Table 2.15-6, Project construction would result in approximately 1,501 metric tons of CO2e over the course of the anticipated 18-month construction period.

All construction contracts include Caltrans Standard Specifications related to air quality.

Section 7-1.02A and 7 1.02C, Emissions Reduction, requires contractors to comply with all laws applicable to the project and to certify they are aware of and will comply with all ARB emission reduction regulations. Section 14-9.02, Air Pollution Control, requires contractors to comply with all air pollution control rules, regulations, ordinances, and statutes. Certain common regulations, such as equipment idling restrictions, that reduce construction vehicle emissions also help reduce GHG emissions.

3.3.3.3 CEQA Conclusion
As discussed in Section 3.2.8 Greenhouse Gas Emissions, neither the Air District nor the City of Napa recommend a GHG emissions threshold of significance for construction emissions. The Project would be required to implement control measures during construction that would limit emissions generated by equipment used (see AMM AIR-

1.1 and 1.2). For these reasons, project construction would not generate a significant amount of GHG emissions.

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As previously discussed, the Project would not result in a change in VMT for the Project area and would not include any stationary sources of GHG emissions. Additionally, the Project may result in less GHG emissions due to reduced vehicle delay (e.g., idling) at the intersection. For these reasons, Project operation would not generate a significant amount of GHG emissions.

At the time of preparation of this Final EIR/EA, the City of Napa has not adopted a GHG Reduction Strategy. The Project would result in no net permanent increase in GHG emissions and could reduce GHG emissions by reducing vehicle idling at the Project intersection. Additionally, by providing a new shared-use path through the Project intersection the Project would be consistent with the 2017 Clean Air Plan Transportation Control Measure TR9: Bicycle and Pedestrian Access and Facilities, which encourages planning for bicycle and pedestrian facilities. Therefore, the Project would not conflict with the 2017 Clean Air Plan or another plan, policy, or regulation adopted for the purpose of reducing GHG emissions. Therefore, the Project would have a less than significant GHG emissions impact.

Caltrans is firmly committed to implementing measures to help reduce GHG emissions.

These measures are outlined in the following section.

3.3.4 Greenhouse Gas Reduction Strategies

3.3.4.1 Statewide Efforts
In response to Assembly Bill 32, the Global Warming Solutions Act, California is implementing measures to achieve emission reductions of GHGs that cause climate change. Climate change programs in California are effectively reducing GHG emissions from all sectors of the economy. These programs include regulations, market programs, and incentives that will transform transportation, industry, fuels, and other sectors to take California into a sustainable, cleaner, low-carbon future, while maintaining a robust economy (ARB 2022b).

Major sectors of the California economy, including transportation, will need to reduce emissions to meet 2030 and 2050 GHG emissions targets. The Governor’s Office of Planning and Research identified five sustainability pillars in a 2015 report: (1) Increasing the share of renewable energy in the State’s energy mix to at least 50 percent by 2030; (2) Reducing petroleum use by up to 50 percent by 2030; (3) Increasing the energy efficiency of existing buildings by 50 percent by 2030; (4) Reducing emissions of short-lived climate pollutants; and (5) Stewarding natural resources, including forests, working lands, and wetlands, to ensure that they store carbon, are resilient, and enhance other environmental benefits (OPR 2015).

The transportation sector is integral to the people and economy of California. To achieve GHG emission reduction goals, it is vital that the state build on past successes in reducing criteria and toxic air pollutants from transportation and goods movement.

GHG emission reductions will come from cleaner vehicle technologies, lower-carbon fuels, and reduction of vehicle miles traveled (VMT). Reducing today’s petroleum use in

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cars and trucks is a key state goal for reducing greenhouse gas emissions by 2030 (California Environmental Protection Agency 2015).

In addition, SB 1386 (Wolk 2016) established as state policy the protection and management of natural and working lands and requires state agencies to consider that policy in their own decision making. Trees and vegetation on forests, rangelands, farms, and wetlands remove carbon dioxide from the atmosphere through biological processes and sequester the carbon in above- and below-ground matter.

Subsequently, Governor Gavin Newsom issued Executive Order N-82-20 to combat the crises in climate change and biodiversity. It instructs state agencies to use existing authorities and resources to identify and implement near- and long-term actions to accelerate natural removal of carbon and build climate resilience in our forests, wetlands, urban greenspaces, agricultural soils, and land conservation activities in ways that serve all communities and in particular low-income, disadvantaged, and vulnerable communities. To support this order, the California Natural Resources Agency released Natural and Working Lands Climate Smart Strategy (California Natural Resources Agency 2022).

3.3.4.2 Caltrans Activities
Caltrans continues to be involved on the Governor’s Climate Action Team as the ARB works to implement EOs S-3-05 and S-01-07 and help achieve the targets set forth in AB 32. EO B-30-15, issued in April 2015, and SB 32 (2016), set an interim target to cut GHG emissions to 40 percent below 1990 levels by 2030. The following major initiatives are underway at Caltrans to help meet these targets.

Climate Action Plan for Transportation Infrastructure
The California Action Plan for Transportation Infrastructure (CAPTI) builds on executive orders signed by Governor Newsom in 2019 and 2020 targeted at reducing GHG emissions in transportation, which account for more than 40 percent of all polluting emissions, to reach the state's climate goals. Under CAPTI, where feasible and within existing funding program structures, the state will invest discretionary transportation funds in sustainable infrastructure projects that align with its climate, health, and social equity goals (California State Transportation Agency 2021).

California Transportation Plan
The California Transportation Plan (CTP) is a statewide, long-range transportation plan to meet our future mobility needs and reduce GHG emissions. It serves as an umbrella document for all the other statewide transportation planning documents. The CTP 2050 presents a vision of a safe, resilient, and universally accessible transportation system that supports vibrant communities, advances racial and economic justice, and improves public and environmental health. The plan’s climate goal is to achieve statewide GHG emissions reduction targets and increase resilience to climate change. It demonstrates how GHG emissions from the transportation sector can be reduced through advancements in clean fuel technologies; continued shifts toward active travel, transit,

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and shared mobility; more efficient land use and development practices; and continued shifts to telework (Caltrans 2021a).

Caltrans Strategic Plan
The Caltrans 2020–2024 Strategic Plan includes goals of stewardship, climate action, and equity. Climate action strategies include developing and implementing a Caltrans Climate Action Plan; a robust program of climate action education, training, and outreach; partnership and collaboration; a VMT monitoring and reduction program; and engaging with the most vulnerable communities in developing and implementing Caltrans climate action activities (Caltrans 2021b).

Caltrans Policy Directives and Other Initiatives
Caltrans Director’s Policy 30 (DP-30) Climate Change (June 22, 2012) established a policy to ensure coordinated efforts to incorporate climate change into Caltrans decisions and activities. Other Director’s policies promote energy efficiency, conservation, and climate change, and commit Caltrans to sustainability practices in all planning, maintenance, and operations. Caltrans Greenhouse Gas Emissions and Mitigation Report (Caltrans 2020) provides a comprehensive overview of Caltrans’ emissions and current Caltrans procedures and activities that track and reduce GHG emissions. It identifies additional opportunities for further reducing GHG emissions from Department-controlled emission sources, in support of Caltrans and State goals.

3.3.4.3 Project-Level GHG Reduction Strategies
The following measures will also be implemented in the project to reduce GHG emissions and potential climate change impacts from the project. • The intersection improvements that would be constructed as part of the Project are designed to reduce vehicle delay and congestion. Therefore, when compared to the No Build Alternative, the Project would result in improved traffic operations and a reduction in VMT, which would translate into reduced GHG emissions. • The Project includes a new shared-use path, which would facilitate bicycle and pedestrian travel in the area, reducing GHG emissions when compared to travel by vehicles.
• During the construction phase, the Project would implement the emissions reduction measures listed in Section 2.15 Air Quality, which would require the use of low-emission construction equipment, prohibit unnecessary idling of trucks and equipment, require the proper maintenance and tuning of equipment, and prohibit the use of diesel-powered generators, all of which would reduce GHG emissions.

3.3.5 Adaptation
Reducing GHG emissions is only one part of an approach to addressing climate change. Caltrans must plan for the effects of climate change on the state’s

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transportation infrastructure and strengthen or protect the facilities from damage.

Climate change is expected to produce increased variability in precipitation, rising temperatures, rising sea levels, variability in storm surges and their intensity, and in the frequency and intensity of wildfires. Flooding and erosion can damage or wash out roads; longer periods of intense heat can buckle pavement and railroad tracks; storm surges combined with a rising sea level can inundate highways. Wildfire can directly burn facilities and indirectly cause damage when rain falls on denuded slopes that landslide after a fire. Effects will vary by location and may, in the most extreme cases, require that a facility be relocated or redesigned. Furthermore, the combined effects of transportation projects and climate stressors can exacerbate the impacts of both on vulnerable communities in a project area. Accordingly, Caltrans must consider these types of climate stressors in how highways are planned, designed, built, operated, and maintained.

3.3.5.1 Federal Efforts
Under NEPA Assignment, Caltrans is obligated to comply with all applicable federal environmental laws and FHWA NEPA regulations, policies, and guidance.

The Fifth National Climate Assessment, published in 2023, presents the most recent science and “analyzes the effects of global change on the natural environment, agriculture, energy production and use, land and water resources, transportation, human health and welfare, human social systems, and biological diversity; [It] analyzes current trends in global change, both human-induced and natural, and projects major trends for the subsequent 25 to 100 years … to support informed decision-making across the United States.” Building on previous assessments, it continues to advance “an inclusive, diverse, and sustained process for assessing and communicating scientific knowledge on the impacts, risks, and vulnerabilities associated with a changing global climate” (U.S. Global Change Research Program 2023).

The National Oceanic and Atmospheric Administration provides sea level rise projections for all U.S. coastal waters to help communities and decision makers assess their risk from sea level rise. Updated projections through 2150 were released in 2022 in a report and online tool (NOAA 2022).

3.3.5.2 State Efforts
Climate change adaptation for transportation infrastructure involves long-term planning and risk management to address vulnerabilities in the transportation system. A number of state policies and tools have been developed to guide adaptation efforts.

California’s Fourth Climate Change Assessment (Fourth Assessment) (2018) provides information to help decision makers across sectors and at state, regional, and local scales protect and build the resilience of the state’s people, infrastructure, natural systems, working lands, and waters. The Fourth Assessment reported that if no measures are taken to reduce GHG emissions by 2021 or sooner, the state is projected to experience an up to 8.8 degrees Fahrenheit increase in average annual maximum daily temperatures; a two-thirds decline in water supply from snowpack resulting in

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water shortages; a 77% increase in average area burned by wildfire; and large-scale erosion of up to 67% of Southern California beaches due to sea level rise. These effects will have profound impacts on infrastructure, agriculture, energy demand, natural systems, communities, and public health (State of California 2018).

Sea level rise is a particular concern for transportation infrastructure in the coastal zone.

Major urban airports will be at risk of flooding from sea level rise combined with storm surge as early as 2040; San Francisco airport is already at risk. Miles of coastal highways vulnerable to flooding in a 100-year storm event will triple to 370 by 2100, and 3,750 miles will be exposed to temporary flooding. The Fourth Assessment’s findings highlight the need for proactive action to address these current and future impacts of climate change.

To help actors throughout the state address the findings of California’s Fourth Climate Change Assessment, AB 2800’s multidisciplinary Climate-Safe Infrastructure Working Group published Paying it Forward: The Path Toward Climate-Safe Infrastructure in California. This report provides guidance on assessing risk in the face of inherent uncertainties still posed by the best available climate change science. It also examines how state agencies can use infrastructure planning, design, and implementation processes to respond to the observed and anticipated climate change impacts (Climate- Safe Infrastructure Working Group 2018).

EO S-13-08, issued in 2008, directed state agencies to consider sea level rise scenarios for 2050 and 2100 during planning to assess project vulnerabilities, reduce risks, and increase resilience to sea level rise. It gave rise to the 2009 California Climate Adaptation Strategy, the Safeguarding California Plan, and a series of technical reports on statewide sea level rise projections and risks, including the State of California Sea- Level Rise Guidance Update in 2018. The reports addressed the full range of climate change impacts and recommended adaptation strategies. The current California Climate Adaptation Strategy incorporates key elements of the latest sector-specific plans such as the Natural and Working Lands Climate Smart Strategy, Wildfire and Forest Resilience Action Plan, Water Resilience Portfolio, and the CAPTI (described above). Priorities in the 2023 California Climate Adaptation Strategy include acting in partnership with California Native American Tribes, strengthening protections for climate-vulnerable communities that lack capacity and resources, implementing nature- based climate solutions, using best available climate science, and partnering and collaboration to best leverage resources (California Natural Resources Agency 2023).

EO B-30-15 recognizes that effects of climate change threaten California’s infrastructure and requires state agencies to factor climate change into all planning and investment decisions. Under this EO, the Office of Planning and Research published Planning and Investing for a Resilient California: A Guidebook for State Agencies, to encourage a uniform and systematic approach to building resilience.

SB 1 Coastal Resources: Sea Level Rise (Atkins 2021) established statewide goals to “anticipate, assess, plan for, and, to the extent feasible, avoid, minimize, and mitigate the adverse environmental and economic effects of sea level rise within the coastal zone.” As the legislation directed, the Ocean Protection Council collaborated with 17

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state planning and coastal management agencies to develop the State Agency Sea- Level Rise Action Plan for California in February 2022. This plan promotes coordinated actions by state agencies to enhance California's resilience to the impacts of sea level rise (California Ocean Protection Council 2022).

3.3.5.3 Caltrans Adaptation Efforts
Caltrans Vulnerability Assessments
Caltrans completed climate change vulnerability assessments to identify segments of the State Highway System vulnerable to climate change effects of precipitation, temperature, wildfire, storm surge, and sea level rise.

The climate change data in the assessments were developed in coordination with climate change scientists and experts at federal, state, and regional organizations at the forefront of climate science. The findings of the vulnerability assessments guide analysis of at-risk assets and development of Adaptation Priority Reports as a method to make capital programming decisions to address identified risks.

Caltrans Sustainability Programs
The Director’s Office of Equity, Sustainability and Tribal Affairs supports implementation of sustainable practices at Caltrans. The Sustainability Roadmap is a periodic progress report and plan for meeting the Governor’s sustainability goals related to EOs B-16-12, B-18-12, and B-30-15. The Roadmap includes designing new buildings for climate change resilience and zero-net energy, and replacing fleet vehicles with zero-emission vehicles (Caltrans 2023).

3.3.5.4 Project Adaptation Analysis
Sea Level Rise
Figure 3.3-4 shows projected sea level rise for the Project area. The map was created using the Caltrans Environmental Geographic Information System (GIS) Viewer, which incorporates sea level rise data from sources including the NOAA, United States Geological Society (USGS), and Caltrans Vulnerability Assessment. Assuming 16.40 feet of sea level rise, the most conservative scenario available, Third Street and portions of SR 121 would be affected by sea level rise. Depths of sea level rise projections for San Francisco, the nearest tide gauge to the Project site, are summarized in Table 3.3-1.

Table 3.3-1: Projected Sea-Level Rise Depths (in feet)
Year Low Risk Aversion Medium Risk
Aversion
High Risk
Aversion
Extreme Risk
Aversion
2030 0.5 0.6 0.8 1.0
2040 0.8 1.0 1.3 1.8
2050 1.1 1.4 1.9 2.7
2060 1.5 1.8 2.6 3.9
2070 1.9 2.4 3.5 5.2

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Year Low Risk Aversion Medium Risk
Aversion
High Risk
Aversion
Extreme Risk
Aversion
2080 2.4 3.0 4.5 6.6
2090 2.9 3.6 5.6 8.3
2100 3.4 4.4 6.9 10.2
2110 3.5 4.5 7.3 11.9
2120 4.1 5.2 8.6 14.2
2130 4.6 6.0 10.0 16.6
2140 5.2 6.8 11.4 19.1
2150 5.8 7.7 13.0 21.9
Source: California Ocean Protection Council. State of California Sea-Level Rise Guidance 2018 Update.

As discussed in Section 2.10 Hydrology and Floodplain, the Project would incorporate fill along Third Street to result in a final grade elevated 4.81 feet above the BFE for a 100-year storm event. Therefore, the Project would also be adequately elevated above sea level in the extreme risk aversion scenario through 2050 and the low risk aversion scenario through 2100. While the Project would experience inundation in the extreme risk aversion scenario for 2100, the extreme risk aversion scenario has less than a 0.5% probability of occurring. For these reasons, impacts due to projected sea-level rise are not expected.

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Caltrans Vulnerability Assessment,

16.40 feet sea level rise
USGS Coastal Storm Modeling System,

16.40 feet sea level rise
0 .05 .1 .2 Miles
Project Site
AREA PROJECTED TO BE AFFECTED BY SEA LEVEL RISE FIGURE 3.3-4

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Precipitation and Flooding
The Project site is depicted on the FEMA Flood Insurance Rate Map panel number 06055C0517F. As shown in Figure 2.10-1, the portion of the Project site located near the Napa River is within the Zone AE Floodplain. Zone AE is defined as a special flood hazard area with a one percent chance of flooding in any given year. A portion of the Project site is also located within an area with a 0.2 percent chance of flooding in any given year. The rest of the Project site is located within Flood Zone X, an area of minimal flood hazard. FEMA’s 100-year water BFE at the Project site is 18.99 feet.

The Project would add fill within the floodplain along Third Street, resulting in a final grade of approximately 23.8 feet (4.81 feet above the BFE). Therefore, the Project would avoid inundation in the event of a 100-year storm event. The Project’s excess of

4.81 feet of elevation above the 100-year BFE would accommodate greater flood elevations in the scenario that storm events become more extreme due to climate change effects.

Wildfire
The Project site is not located in or near state responsibility areas or lands classified as very high fire hazard severity zones. There are areas of local responsibility classified as moderate fire hazard zones along Coombsville Road near the City’s limits, approximately a half-mile east of the Project site.43 The Project would not exacerbate wildfire risk within the moderate fire hazard zone or anywhere else. As previously described, access through intersection would be maintained throughout construction and potential detours would be scheduled in coordination with NFD as needed. Project operation would result in improved access and safety through the intersection. For these reasons, the Project would not impact evacuation routes or otherwise result in wildfire impacts.

Temperature
The District Climate Change Vulnerability Assessment does not indicate temperature changes during the project’s design life that would require adaptive changes in pavement design or maintenance practices.

43 CAL FIRE. City of Napa – Napa County Local Responsibility Area Fire Hazard Severity Zones. Adopted February 24, 2025. https://calfire.app.box.com/file/1785863301140

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3.4 EIR Alternatives
CEQA requires that an EIR identify and evaluate alternatives to a project as it is proposed. Two key provisions from the CEQA Guidelines pertaining to the discussion of alternatives are included below:

Section 15126.6(a). Consideration and Discussion of Alternatives to the Proposed Project. An EIR shall describe a range of reasonable alternatives to the project, or to the location of the project, which would feasibly attain most of the basic objectives of the project but would avoid or substantially lessen any of the significant effects of the project, and evaluate the comparative merits of the alternatives. An EIR need not consider every conceivable alternative to a project. Rather it must consider a reasonable range of potentially feasible alternatives that will foster informed decision making and public participation. An EIR is not required to consider alternatives which are infeasible. The lead agency is responsible for selecting a range of project alternatives for examination and must publicly disclose its reasoning for selecting those alternatives. There is no ironclad rule governing the nature or scope of the alternatives to be discussed other than the rule of reason.

Section 15126.6(b). Purpose. Because an EIR must identify ways to mitigate or avoid the significant effects that a project may have on the environment (Public Resources Code Section 21002.1), the discussion of alternatives shall focus on alternatives to the project or its location which are capable of avoiding or substantially lessening any significant effects of the project, even if these alternatives would impede, to some degree, the attainment of the project objectives, or be more costly.

Other elements of the CEQA Guidelines discuss that alternatives should include enough information to allow a meaningful evaluation and comparison with the proposed project.

The CEQA Guidelines state that if an alternative would cause one or more additional impacts, compared to the proposed project, the discussion should identify the additional impact, but in less detail than the significant effects of the proposed project.

The three critical factors to consider in selecting and evaluating alternatives are: (1) the significant impacts from the project that could be reduced or avoided by an alternative, (2) consistency with the project’s objectives, and (3) the feasibility of the alternatives available. Each of these factors is discussed below.

3.4.1 Significant Impacts from the Project

3.4.1.1 Significant Unavoidable Impacts
As previously described in Section 2.9 and 3.2.5 Cultural Resources, the Project would result in a significant and unavoidable impact to the East Napa Historic District by demolishing the contributing residential property at 801 Silverado Trail.

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3.4.1.2 Less than Significant Impacts with Mitigation Incorporated Alternatives may also be considered if they would further reduce impacts that are already less than significant because of required or proposed mitigation. As described in Section 2.16 Noise and Vibration and 3.2.13 Noise, the Project would result in potentially significant construction vibration impacts to several neighboring buildings, though impacts would be reduced to a less than significant level with incorporation of MM NOI-2.1 through MM NOI-2.3.

3.4.2 Project Objectives
Pursuant to CEQA Guidelines Section 15124, the EIR must include a statement of the objectives sought by the proposed project. While CEQA does not require that alternatives be capable of meeting all of the project objectives, their ability to meet most of the objectives is considered relevant to their consideration. As described in Section

1.2 Purpose and Need, the objectives of the Project include the following:
• I mprove the operations of the intersection that will result in reduced driver delay, reduced congestion, and, therefore, an overall improvement to intersection operations.
• I mprove the safety and accessibility for all users of the intersection. • I mprove bicycle and pedestrian facilities at the intersection as well as meet Americans with Disabilities Act (ADA) requirements.

3.4.3 Alternatives Analysis
As previously discussed in Section 1.7 Alternatives Considered But Eliminated From Further Discussion Prior To The Draft Environmental Document, three build alternatives were identified in the PID phase; the Build Alternative, Alternative 6 (Five-Legged Roundabout), and Alternative 8 (Two Roundabouts). While both alternatives would avoid a full acquisition of the property at 801 Silverado Trail and demolition of the associated residence, the Five-Legged Roundabout Alternative would result in a full acquisition of 1010 East Avenue, a multi-family residential property with two residences.

The Two Roundabouts Alternative would only require partial acquisition and driveway realignment of the 1010 East Avenue property and would not result in any other residential acquisitions. Both alternatives are discussed in this section to determine their potential to avoid or reduce the significant impacts of the project.

3.4.3.1 Five-Legged Roundabout Alternative
The Five-Legged Roundabout Alternative would replace the existing intersection with a single, five-legged roundabout. The single roundabout would be centered slightly east of the existing intersection and incorporate all of the adjoining roadways. The Five-Legged Roundabout Alternative would result in a full acquisition of three commercial properties and full acquisition of a residential property, potentially resulting in social and economic

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impacts to the local community. The potential right-of-way impacts are summarized below:
a) Napa Marble & Granite Works (9 Coombsville Road) is a monument and grave marker business. The property would be completely within the footprint of the roundabout and would require full acquisition.
b) Posh Motors is a used car dealership which uses the parking lot on their property to store and display inventory. This alternative may eliminate both existing driveways for the Posh Motors (800 Silverado Trail) property. If both driveways are eliminated, full acquisition of the property would be required. c) Napa Tire & Wheels (713 Silverado Trail) is an automobile service business. The southbound SR 121 exit from the five-legged roundabout would impact the existing overhang/carport structure on the property. Both existing driveways would be impacted, and there may not be a suitable location to provide a new driveway that gives sufficient distance from the roundabout. Discussion with the business owners will determine if full acquisition is required. Additionally, due to the nature of the business, contaminated soils are likely present in the area. d) 1010 East Avenue is a multi-family residential property with two residences that would be directly impacted by this alternative. The main residence is within the alignment for East Avenue and would require demolition. An additional residence is directly adjacent to the improvements and a new driveway access to the property may be infeasible, requiring full acquisition of the property.

Comparison of Environmental Impacts
Aesthetics
This alternative would result in more visual changes to the Project area because it would require full acquisition of several commercial and residential properties and demolition of existing structures. Similar to the Build Alternative, this alternative would also result in tree removals, reconfiguration of the existing intersection, and new sources of lighting.

Agriculture and Forestry Resources
Similar to the Build Alternative, this alternative would not impact any agriculture or forestry resources.

Air Quality
Similar to the Build Alternative, this alternative would not increase vehicle trips through the intersection or otherwise result in permanent air quality impacts. Construction air quality emissions would be greater than the Build Alternative because several more structures would need to be demolished during the construction phase.

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Biological Resources
This alternative would impact the same habitat types as the Build Alternative and would result in a comparable number of tree removals. The Five-Legged Roundabout Alternative would result in a similar level of impacts to biological resources as the Build Alternative.

Cultural Resources
This alternative would result in a similar level of potential impacts to archaeological resources during project construction. However, the alternative would avoid demolition of the residence at 801 Silverado Trail and, therefore, would not result in a significant impact to the East Napa Historic District. For this reason, the Five-Legged Roundabout Alternative would result in a lesser level of impact on cultural resources. The properties that would be demolished for construction of this alternative were found not to be eligible for listing on the CRHR or NRHP.

Energy
This alternative would result in comparable levels of energy consumption as the Build Alternative during both the construction and operational phases.

Geology and Soils
This alternative would result in similar impacts associated with geology and soils because it would be constructed in the same location as the Build Alternative.

Hazards and Hazardous Materials
This alternative would result in similar impacts associated with hazards and hazardous materials because it would be a similar project type constructed in generally the same location as the Build Alternative. Additional soil remediation and monitoring may be required due to the acquisition of the Napa Tire & Wheels property but it would not significantly increase impacts from the Project.

Hydrology and Water Quality
Similar to the Build Alternative, the Five-Legged Roundabout Alternative would likely result in a net increase in impervious surfaces on-site and would be partially located within a flood hazard zone but impacts to water quality would be less than significant through compliance with the MS4 Permit.

Land Use and Planning
Similar to the Build Alternative, the Five-Legged Roundabout Alternative would not divide an existing community and would be consistent with the City’s goals and policies to improve traffic circulation and bicycle and pedestrian facilities. However, this alternative would also result in the demolition of at least one residential structure.

Additionally, the Five-Legged Roundabout Alternative would require full acquisition of

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three commercial properties and the demolition of several commercial structures occupied by existing businesses.

Mineral Resources
This alternative would not have any impact on mineral resources.

Noise
Similar to the Build Alternative, the Five-Legged Roundabout Alternative would not increase traffic in the Project area but it would alter the existing geometry of the intersection. This alternative would not substantially increase ambient noise at nearby receptors. This alternative would result in similar construction noise and vibration impacts as the Build Alternative and would require mitigation to reduce impacts to a less than significant level.

Population and Housing
Similar to the Build Alternative, this alternative would not induce population growth. The Five-Legged Roundabout Alternative would displace residents due to the full acquisition of one residential property. This would be a similar impact to the Build Alternative, which would demolish one residence.

Public Services
Similar to the Build Alternative, this alternative would not result in any permanent impacts to public services. A TDM would still be prepared to ensure adequate emergency access is provided throughout construction.

Recreation
Similar to the Build Alternative, this alternative would not result in any impacts to recreation facilities.

Transportation
Similar to the Build Alternative, the Five-Legged Roundabout Alternative would not result in any changes in VMT and would incorporate bicycle and pedestrian facilities into the roundabouts. A TMP would be prepared to ensure adequate emergency access is provided throughout construction. This alternative would not introduce any incompatible uses and would be designed in accordance with current highway and roundabout design standards.

Tribal Cultural Resources
This alternative would result in a similar level of potential impacts to tribal cultural resources during project construction.

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Utilities and Service Systems
Similar to the Build Alternative, this alternative would not result in a substantial increase in demand on utility services. The only utility usage associated with the Build Alternative would be landscape irrigation and electricity for lighting. Similar to the Build Alternative, the Five-Legged Roundabout Alternative would likely require the relocation of existing utilities to accommodate the proposed roundabout.

Wildfire
Similar to the Build Alternative, the Five-Legged Roundabout Alternative would not exacerbate wildfire risk.

Relationship to Objectives
Although the Five-Legged Roundabout Alternative would provide accessibility for all users and improve operations over existing conditions, the implementation of cumulative projects in the area would result in operational deficiencies on Third Street (LOS E). This would not meet the project objectives to improve intersection operations and reduce vehicle delay and congestion to the same extent as the Build Alternative.

Conclusion
The Five-Legged Roundabout Alternative would avoid demolishing the residence at 801 Silverado Trail and, therefore, would avoid a significant impact to the East Napa Historic District. Because this alternative would result in long-term operational deficiencies on Third Street, it would not meet the Project objectives to the same extent as the Build Alternative.

3.4.3.2 Two Roundabout Alternative
The Two Roundabout Alternative would replace the existing intersection with two, single-lane roundabouts. Unlike the Build Alternative, this alternative would align Third Street to the southern roundabout along with Coombsville Road and SR 121. The northern roundabout would be a three-legged roundabout with SR 121 and East Avenue. The Two Roundabout Alternative would result in a full acquisition of three commercial properties and a major or full acquisition of a fourth commercial property, potentially resulting in social and economic impacts to the local community. The potential right-of-way impacts are summarized below:
a) Posh Motors is a used car dealership which uses the parking lot on their property to store and display inventory. This alternative would require acquisition of a significant portion of the parking area, which eliminates the commercial viability of the property as a car dealership. A full acquisition would be anticipated. b) Third Street would be realigned through the center of the Napa Tire & Wheels property, and a full acquisition would be required. Due to the nature of the business, contaminated soils are likely present in the area.

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c) Both existing driveways to the Napa Marble & Granite Works property would be eliminated and there are no viable locations to provide a new driveway. A full acquisition would be required.
d) The commercial center on the southeast corner of Third Street and Juarez Street includes multiple businesses, including an appliance store, plumbing showroom, and children’s event venue. Third Street would be realigned through the property, requiring demolition of a portion of the existing building. Some commercial utility of the remaining unused property may be possible, and an existing driveway onto Juarez Street would remain. Major acquisition would be anticipated, though full acquisition may be required depending on discussions with the property owners. e) The residential property at 1010 East Avenue would require partial acquisition and may require driveway realignment.

Comparison of Environmental Impacts
Aesthetics
This alternative would result in more visual changes to the Project area because it would require full acquisition of several commercial properties and demolition of existing structures. Similar to the Build Alternative, this alternative would also result in tree removals, reconfiguration of the existing intersection, and new sources of lighting.

Agriculture and Forestry Resources
Similar to the Build Alternative, this alternative would not impact any agriculture or forestry resources.

Biological Resources
This alternative would impact the same habitat types as the Build Alternative and would result in a comparable number of tree removals. The Two Roundabout Alternative would result in a similar level of impacts to biological resources as the Build Alternative.

Cultural Resources
This alternative would result in a similar level of potential impacts to archaeological resources during project construction. However, the alternative would avoid demolition of the residence at 801 Silverado Trail and, therefore, would not result in a significant impact to the East Napa Historic District. For this reason, the Two Roundabout Alternative would result in a lesser level of impact on cultural resources. The

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commercial properties that would be demolished for construction of this alternative were found not to be eligible for listing on the CRHR or NRHP.

Energy
This alternative would result in comparable levels of energy consumption as the Build Alternative during both the construction and operational phases.

Geology and Soils
This alternative would result in similar impacts associated with geology and soils because it would be constructed in the same location as the Build Alternative.

Greenhouse Gas Emissions
Similar to the Build Alternative, this alternative would not increase vehicle trips through the intersection or otherwise result in a permanent increase in GHG emissions.

Construction GHG emissions would be comparable to the Build Alternative.

Hydrology and Water Quality
Similar to the Build Alternative, the Two Roundabout Alternative would likely result in a net increase in impervious surfaces on-site and would be partially located within a flood hazard zone but impacts to water quality would be less than significant through compliance with the MS4 Permit.

Land Use and Planning
Similar to the Build Alternative, the Two Roundabout Alternative would not divide an existing community and would be consistent with the City’s goals and policies to improve traffic circulation and bicycle and pedestrian facilities. Additionally, this alternative would not require full acquisition of any residential properties or the demolition of any residential structures. However, the Two Roundabout Alternative would require full acquisition of four commercial properties and the demolition of several commercial structures occupied by existing businesses.

Mineral Resources
This alternative would not have any impact on mineral resources.

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Noise
Similar to the Build Alternative, the Two Roundabout Alternative would not increase traffic in the Project area but it would alter the existing geometry of the intersection. This alternative would not substantially increase ambient noise at nearby receptors. This alternative would result in similar construction noise and vibration impacts as the Build Alternative and would require mitigation to reduce impacts to a less than significant level.

Population and Housing
Similar to the Build Alternative, this alternative would not induce population growth. The Two Roundabout Alternative would not displace any people because it would not require full acquisition of any residential properties. This would be a lesser impact than the Build Alternative, which would demolish one residence.

Recreation
Similar to the Build Alternative, this alternative would not result in any impacts to recreation facilities.

Transportation
Similar to the Build Alternative, the Two Roundabout Alternative would not result in any changes in VMT and would incorporate bicycle and pedestrian facilities into the roundabouts. A TMP would be prepared to ensure adequate emergency access is provided throughout construction. This alternative would not introduce any incompatible uses and would be designed in accordance with current highway and roundabout design standards.

Tribal Cultural Resources
This alternative would result in a similar level of potential impacts to tribal cultural resources during project construction.

Utilities and Service Systems
Similar to the Build Alternative, this alternative would not result in a substantial increase in demand on utility services. The only utility usage associated with the Build Alternative would be landscape irrigation and electricity for lighting. Similar to the Build Alternative, the Two Roundabout Alternative would likely require the relocation of existing utilities to accommodate the proposed roundabouts.

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Wildfire
Similar to the Build Alternative, the Two Roundabout Alternative would not exacerbate wildfire risk.

Relationship to Project Objectives
The AM and PM peak hour queues for southbound vehicles on SR 121 entering the southern roundabout would likely extend more than 150 feet, which is the available distance between the two roundabouts. This would result in the queue spilling back into the northern roundabout, creating significant delay. This would not meet the project objectives to improve intersection operations and reduce vehicle delay and congestion to the same extent as the Build Alternative.

Conclusion
The Two Roundabout Alternative would avoid demolishing the residence at 801 Silverado Trail and, therefore, would avoid a significant impact to the East Napa Historic District. Because this alternative would result in queuing and significant delays during the AM and PM peak hours, it would not meet the Project objectives to the same extent as the Build Alternative.

3.4.4 Environmentally Superior Alternative
The CEQA Guidelines state that an EIR shall identify an environmentally superior alternative. Based on the above discussion, the environmentally superior alternative to the proposed project is the No Project Alternative because all of the project’s significant environmental impacts would be avoided. However, Section 15126.6(e)(2) states that “if the environmentally superior alternative is the No Project Alternative, the EIR shall also identify an environmentally superior alternative among the other alternatives.” In addition to the No Project Alternative, the Two Roundabout Alternative would avoid the significant cultural resource impact to the East Napa Historic District and avoid full acquisition of residential property to accommodate the Project. Based on the discussion above, the environmentally superior alternative would be the Two Roundabout Alternative as it would reduce the cultural resource impact of the project and avoid full residential property acquisition.

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Chapter 4 Comments and Coordination

4.1 INTRODUCTION
Early and continuing coordination with the general public and public agencies is an essential part of the environmental process. It helps planners determine the necessary scope of environmental documentation and the level of analysis required, and to identify potential impacts and avoidance, minimization, and/or mitigation measures and related environmental requirements. Agency and tribal consultation and public participation for this project have been accomplished through a variety of formal and informal methods, including interagency coordination meetings, public meetings, public notices, Project Development Team (PDT) meetings, community workshops, and meetings with property and business owners. This chapter summarizes the results of Caltrans’s efforts to fully identify, address, and resolve project-related issues through early and continuing coordination.

This chapter summarizes the efforts to fully identify, address, and resolve Project- related issues through early and continuing coordination.

4.2 NOTICE OF PREPARATION AND SCOPING PROCESS
The City of Napa circulated a Notice of Preparation (NOP) of an EIR to local, regional, state, and federal agencies on July 29, 2024. The 30-day scoping period started on July 29, 2024, and ended on August 28, 2024. A copy of the NOP is provided in Appendix E.

Two public comment letters were received during the scoping period. The first letter, from the NAHC, was related to AB 52 and SB 18 requirements and the NAHC’s recommendations for cultural resources assessments. The second letter, from CDFW, was related to regulatory requirements for biological resources, the environmental setting, CDFW’s recommendations for impact analysis and mitigation measures, environmental data, and filing fees.

4.3 CONSULTATION AND COORDINATION WITH AGENCIES AND

ORGANIZATIONS
Caltrans, the City of Napa, and NVTA meet on a regular basis to address any questions or issues related to Project design, construction, and planned operation.

4.4 DRAFT EIR/EA COMMENTS AND RESPONSES
The Draft EIR/EA was circulated to the public from August 28, 2025 to November 1, 2025. A public meeting was held on September 17, 2025, from 7:00pm to 8:30pm at the Alta Heights Elementary School Multi-Purpose Room (15 Montecito Boulevard, Napa).

The availability of the Draft EIR/EA for review and comment was advertised and noticed through a range of outreach methods. Each of the advertisements and notices provided information on how to obtain and review the Draft EIR/EA, how to comment, the

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deadline for comments, how to participate in the public meeting, and who to contact for more information. A Notice of Completion (NOC) was posted with the California State Clearinghouse (SCH) on September 2, 2025, identifying the start and end dates of the public review period (SCH #2024071257), and the NOC was distributed through the SCH to a wide range of State agencies and commissions. A Notice of Availability was filed with the Napa County Clerk-Recorder Office on August 28, 2025. This notice was emailed to elected officials, agencies, organizations, and community stakeholders (see Chapter 6). In addition, this notice was mailed to residences and businesses within a 500-foot radius of the Project through the U.S. Postal Service. The notice was also published in The Napa Valley Register newspaper and posted on Caltrans’ website. A link to Caltrans’ website was provided on the City of Napa’s webpage for the Project.

The list of written comments received on the Draft EIR/EA, including the page on which the written response(s) to the comment begins, is shown below. A copy of each document is contained in Appendix J.

Comment # 1:Aracne, Steve and Kathy, September 23, 2025 .................................... 192 Comment # 2: Bristol, John, October 17, 2025 ........................................................... 192 Comment # 3: Cuny, Steve, September 19, 2025 ....................................................... 193 Comment # 4: Daglia, Elizabeth, September 17, 2025 ................................................ 194 Comment # 5: Garcia, Carmen, September 17, 2025 ................................................. 195 Comment # 6: Hawker, Patti, September 22, 2025 ..................................................... 195 Comment # 7: Hazelhoff, Karna, September 19, 2025 ................................................ 196 Comment # 8: Lindley, Rian, September 17, 2025 ...................................................... 197 Comment # 9: Lucas, Janis, October 11, 2025 ........................................................... 198 Comment # 10: Open House Comment Cards, September 17, 2025 ......................... 198 Comment # 11: Stromberger, Karla, September 18, 2025 .......................................... 201 Comment # 12: Wyman, Lynn, October 4, 2025 ......................................................... 203 Comment # 13: Zeichner, Daniel, and Lockman, Elizabeth, September 15, 2025 ...... 204

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Comment # 1: Aracne, Steve and Kathy, September 23, 2025 Comment 1-A: We live at 25 Highland Dr. We have a home in another Bay Area city.

Several years ago they were on the same movement regarding roundabouts. The accident rate went up significantly and the roundabouts were removed. We see the chaos at the one installed at the highway 29 interchange. Napa engineering needs to stop reinventing the wheel. Thank you.

Response 1-A: The Project would be designed to current roundabout design standards and safety provisions for pedestrians and bicyclists, including ADA compliant facilities, would be provided. The use of roundabouts has been shown to reduce the severity of vehicular crashes. Based on the City’s review of accident data at the roundabouts adjacent to Highway 29, the number of injury accidents at this location have decreased from seven annually to less than three annually following installation of the roundabouts.

The Project would also reduce congestion and vehicle delay while improving safety for all users.

Comment # 2: Bristol, John, October 17, 2025
Comment 2-A: 1.4.1.2 Pedestrian and Bicycle Safety. A 10-foot wide shared-use path will be provided throughout the new roundabout(s) buffered by at least 2 feet of landscaping from the roadway, please make the landscaping butterfly friendly.

Response 2-A: Caltrans requires that native plantings be used in roadway landscaping, whenever feasible. The landscape plans for the Project will incorporate native wildflowers and grasses to support native species and wildlife, including butterflies.

Comment 2-B: 1.4.1.6 Utilities. Due to the grading that will be required to construct the new roundabouts, relocation of the City water transmission line that runs from 3rd Street as well as up to six joint utility poles will need to be relocated or undergrounded. In addition to relocating the water pipe, we must install and extend the Napa Sewer District purple pipe re-cycled water, to go though this new round about.

Response 2-B: The commenter’s request for recycled water to be extended to the Project area is acknowledged. The Project will relocate an existing water transmission line on Third Street. During the final design phase of the Project, the City will work with the utility companies to develop a relocation plan for all impacted utilities. The Project does not propose to extend any new utilities to the Project area at this time.

Comment 2-C: 2.7.2.2 Bicycle and Pedestrian Facilities Class II bicycle facilities. Bike path from the Vine trail, along all of 3rd street, to go through the from the Vine trail along third, though 5-way interception all the way to the middle school.

2.7.2.2. The 5-way intersection needs to line up walking paths/sidewalks coming from and to the new highline river trail. There must also be a plan for the BottleRock music event planned each year. Plus a plan for school children to cycle to Silverado Middle School.

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Response 2-C: The Project will provide bicycle and pedestrian facilities through the intersection. The proposed roundabouts will include pedestrian activated Rectangular Rapid Flashing Beacons (RRFB) push buttons to alert vehicular traffic of pedestrian and bicyclist crossings. The Project bicycle and pedestrian improvements will extend on Third Street to Juarez Street and will conform to the existing facilities on East Avenue and Coombsville Road east of the proposed roundabouts.

During major events with large number of pedestrians present, event permit requirements will dictate use of traffic controls to assist with allowing pedestrian crossing of the intersection and traffic flows in the vicinity of the Project. The use of RRFBs will aid drivers in recognizing the presence of pedestrians and bicyclists intending to cross the street.

Comment 2-D: Five-Way Intersection Improvements, what we need, art in the center of the roundabouts.

Native plants and Oak trees to be planted.

Response 2-D: This comment is acknowledged. As described in AMM VIS-1.2 (see Section 2.8 Visual/Aesthetics), the roundabouts, medians, and parkway strips shall be landscaped where feasible. Decorative paving shall be used for areas too narrow to plant or where planting is not easily maintained. Caltrans requires that native plantings be used in roadway landscaping, whenever feasible. The final design for the provision of art and landscaping for the Project will be determined during the Project plans, specifications, and estimates (PS&E) phase.

Comment 2-E: Underground the power lines, for fire safety. Should you approve this site, you must underground the PG&E lines to make the fire hazards safter.

Purple pipe from NSD. This project must extend the purple pipes through the new 5-way interception, to get the pipes ready to feed water to the Napa Expo. This water can refill the water tanks of all the fire trucks that use the Expo in large fires.

Response 2-E: Please see Response 2-B.

Comment 2-F: NVTA and NVUSD buses need to have a GPS unit that works in conjunction with the traffic lights, so when a bus is arriving at the traffic lights at First St, they are set to give priority to the bus. That way buses are flowing through this side of town.

Comment 2-F: This comment is acknowledged. The Project does not propose any improvements to any First Street intersections at this time.

Comment # 3: Cuny, Steve, September 19, 2025
Comment 3-A: It would not be smart to do anything with this intersection based on school traffic for ~30 minutes each school day. Sure it backs up but there are alternative ways to leave this area. To make this expensive change would require removing all the lights and making it almost impossible to cross Silverado from the Coombsville or Alta

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Heights area to walk to town or the Fair Grounds. On a normal day, people do not have long waits at these lights and the pacing is just fine in all directions. Yes, it gets backed up on the Silverado Trail at certain times, but this will not make that any smoother.

I would vote no to trying to fix something that does not need to be fixed! Response 3-A: Based on traffic data and engineering analysis, the intersection has been identified as one of the most congested in the City of Napa with a projected deterioration in operations due to the expected growth in population in the vicinity of the Project. The Project will improve future intersection operations to at least level of service (LOS) B. As summarized in Table 2.7 3, level of service can range from “LOS A”, representing free-flow conditions, to “LOS F”, representing jammed/over-saturated conditions. The Project includes safe crossings meeting current design standards for pedestrians, bicyclists, and the disabled, therefore, improving operations and safety for all users.

Comment # 4: Daglia, Elizabeth, September 17, 2025
Comment 4-A: I live up on Montecito Blvd and the 5 way light works just fine! Sometimes I cut through Silverado from side streets and we have a light at First St.

We need a store where Vallergas is, that too, will help with less traffic, keeps people from driving to other grocery stores, round a about is a waste of money and endless construction!
It does not make sense, weird!
The day care, I fought, omg, lunacy!
I called Utah HQ’s, "are all the children mormon?"
Now, why didn't I think of that?!
I am in contact with their main guy that is the middleman and church is now cyclone fenced, nobody now, can continue to trespass, not even up the stairs off of Montecito.

I told him, "I hope the church is torn down, we get our view back and a nice developer comes in and builds some luxury homes.

Response 4-A: The commenter’s opinion that the current five-way intersection operates adequately is acknowledged. Based on traffic data and engineering analysis, the intersection has been identified as one of the most congested in the City of Napa with a projected deterioration in operations due to the expected growth in population in the vicinity of the Project. The Project would improve future intersection operations to LOS B and improve operations for all users.

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Comment # 5: Garcia, Carmen, September 17, 2025
Comment 5-A: 891 Silverado Trail: Garcia family please don’t put a sound wall in front of a restaurant property. Also please factor in the water that comes down the hill with no street drainage. Thank you!
Response 5-A: The commenter’s request for no soundwall in front of the El Rancho Grande Restaurant is acknowledged. The Project does not currently propose a soundwall at the El Rancho Grande Restaurant parcel. The City met with the property owner and tenant of the property and no soundwall was requested. Based on public comments received during the circulation of the EIR/EA, there have been no requests for a soundwall to be constructed as part of the Project.

The Project will construct stormwater facilities consistent with the City’s MS4 permit that provide treatment and drainage for stormwater runoff from the roadway. The Project will improve drainage in the area for adjacent parcels.

Comment # 6: Hawker, Patti, September 22, 2025
Comment 6-A: I am writing to voice my concern regarding the proposed round about at the intersection of Silverado Trail, 3rd Street, Coombsville Road and East Avenue. I have been a resident in Napa for over 35 years, 31 in Alta Heights. I find this proposal very troubleshome to say the least. This intersection not only controls traffic flow on Silverado Trail moving north and south but also as an entrance and exit to and from Alta Heights, Coombsville Road and Third Street traveling east and west. While there may be some short delays due to stop light activity, I have to say on the whole traffic flows quiet well also maximizing parental drop off and pick up for Alta Heights Elementary and Silverado Middle school. There are additional plans for ANOTHER school on Monticito in the near future. There are numerous events at Napa Valley Fairgrounds that also travel these same routes to Soscol Avenue and beyond, especially the huge flow from Bottle Rock each year. I do not believe that adding a round about to this area would continue to be cohesive to the successful movement of traffic and pedestrians. Not only does Bottle Rock bring in extra vehicle traffic, the foot traffic is enormous. I question how a round about would be conducive with this large pedestrian activity? Please stop and reconsider. Please visit the site for a few hours each day to watch the traffic flow, especially during drop off and pick up of children as they attend school.

Please think about how the construction of something this large would impact these residents and businesses on the out skirts of the site, plus the affects on current traffic flow. Please stop and reconsider.

Response 6-A: The design team reviewed statistical data for roundabouts that shows they typically improve operation and safety at intersections. Future growth in the Project area, including potential additional traffic due to opening a new school, would be better accommodated by the Project during peak traffic hours with at least an LOS B as shown in Table 2.7-7. Modern roundabouts are designed to provide efficient and safe access for all modes of travel, including pedestrians and bicyclists. These principal benefits will apply to the operation of the roundabouts during special events when there are greater volume of pedestrian and vehicular traffic present. Traffic control during large events will

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stop pedestrian traffic, as needed, to allow continued vehicular access through the intersection.

Preparation and approval of a Traffic Management Plan (TMP) will be required prior to project construction. As discussed in the EIR/EA, the TMP will identify detour routes as needed and will address all aspects of construction including, but not limited to, traffic handling in each stage of construction, pedestrian safety/access, and bicycle safety/ access. The TMP will consider the access and traffic handling requirements for special events at the Napa Valley Expo, school schedules, and emergency access (refer to Section 2.7.3 of this EIR/EA).

Comment # 7: Hazelhoff, Karna, September 19, 2025
Comment 7-A: Thank you for taking the time to answer questions regarding the proposed redesign.

Being European, I understand the value of roundabouts and how they work, most importantly, how to drive through them safely and avoid an accident.

My concerns and questions are threefold: is there any proposal to teach people how to drive on them? I was almost broadsided last month by a truck on the First St roundabout crossing in front of me from the LEFT lane onto California. It was terrifying.

Americans really have NO IDEA how to navigate these roundabouts. Not to mention the lack of awareness. I spoke to an NVTA planner who said, “People will get used to it”. Actually, people need instructions because someone will get killed, and THEN there will be an outcry. Always the way it goes. I urge the city to provide instructions on how to drive on them, as more and more roundabouts are being built. Again, I am all in favor of them; they work great to help traffic flow.

Response 7-A: Thank you for your comment. The City of Napa has posted several links to instructional videos on how to safely navigate roundabouts on the Project webpage at https://www.cityofnapa.org/378/Five-Way-Intersection-Project.

Comment 7-B: My second and most important question is, how will you mitigate the intense and prolonged construction congestion around this area? You have two or three schools that release all their students at the same time. I am two years new to Napa, and I've heard that another school is opening? Then, how will Bottlerock, the Fair, and all the events at the Expo Center be handled? If First Street is the way around, have you considered how this will affect those residents? And you cannot get past the Silverado School congestion at 3:00 pm. Forget it, it’s a nightmare.

As much as I love the roundabout idea, the two years of construction are enough for me NOT to want this to happen. It will be a HUGE inconvenience, and more so for residents than the tourists.

Response 7-B: The first order of the construction work would be to clear the additional space needed to construct the roundabouts. This additional space will be used to stage construction work, strategically shifting traffic at appropriate time(s), within the entire

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Project site with minimal disruption to flow of traffic. However, some degree of inconvenience and disruption to normal flow of traffic will be unavoidable.

Preparation and approval of a Traffic Management Plan (TMP) will be required prior to project construction. As discussed in the EIR/EA, the TMP will identify detour routes, as needed, and will address all aspects of construction including, but not limited to, traffic handling in each stage of construction, pedestrian safety/access, and bicycle safety/ access. The TMP will consider the access and traffic handling requirements for special events at the Napa Valley Expo, school schedules, and emergency access (refer to Section 2.7.3 of this EIR/EA).

Comment 7-C: Third and last question- how is this being funded? I never received a straightforward answer on this, just as I didn't on the question of mitigating the massive inconvenience of the construction. A man told me, when I asked this, “Oh, that’s the magic of planning”… I pressed him again, and he had NO idea at all how this was going to be handled.

Thank you for hearing me out. I would like to suggest some solutions, but I have none. I heard that many people are unhappy about this, except for the NVTA person who took 45 minutes of my time trying to sell me on how great this was. I’m not convinced.

Response 7-C: This project is being funded through multiple sources including State Highway Operation and Protection Program (SHOPP) funds at the State level, and local and regional funds through programs such as the Regional Improvement Program (RIP), Congestion Mitigation and Air Quality (CMAQ) and others. Additional funding will be sought through grants and Federal-aid funding.

Comment # 8: Lindley, Rian, September 17, 2025
Comment 8-A: Firstly, I want to thank the team for listening to ideas on communication as it there seems to have more transparency regarding meetings for locals.

However, I was again disappointed to read the EIR and see that 801 Silverado Trail was still on the demolition block. I am sure that many of you on the committee are not local, both working for the state of California and even those working for the city of Napa. For those who are not aware, 801 Silverado Tr. is a local piece of history. Every Christmas there is a beautiful tree that is decorated in the big picture window- families for generations would drive by to see the tree during the holidays. If you ask anyone who grew up in this town they will tell you the same story.

Not only is this house a piece of living history, having been built in 1941, but it is one man's family home. A home that is going to be demolished for the most recent fad in road rehabilitation- roundabouts. Ask anyone who is actually a local, and they will tell you they go out of the way to avoid the roundabouts at First St, and the Soscol interchange.

I have lived in Napa my entire life, almost five decades, twenty years of them in this current home. Not once has anyone taken any measures to "fix" the five-way. It is now suddenly suspicious that Napa/CA has an interest. Could it be because of Bottlerock-

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which is the city of Napa's cash cow. Is it for tourists? Because, it sure has never been about the locals. If it had ever been for the locals, there would have been better timed lights, signs, and improved lighting. It is not about the locals to take an old man's home.

It is not about the locals to have traffic diverted to Juarez St which is already treated like a highway by those avoiding the traffic lights at the five way. It will become a death trap when traffic is diverted for this project, that is for sure.

I've sat through enough meetings with the city council to know that minds have already been made up. This is a done deal, and your meetings are merely a box to check that you have all met the required number of meetings. You could have and should done better by Mr. Rossi- shame on all of you.

Response 8-A: The demolition of the residence at 801 Silverado Trail has been identified as an adverse effect under NEPA and a significant unavoidable impact under CEQA in this EIR/EA, as described in Section 2.9 Cultural Resources and Section 3.2.5 Cultural Resources. As described in MM CULT-1.1, specific mitigation measures will be carried out in accordance with a Memorandum of Agreement to be developed between Caltrans and the State Historic Preservation Officer.

The City acknowledges the holiday tree as an important community landmark and is seeking ways to commemorate the property and its significance to local residents through the MOA and final design process for the Project.

Comment # 9: Lucas, Janis, October 11, 2025
Comment 9-A: Proposed roundabout is a bad idea. This is a nostalgic 5 way intersection unique to Napa. The stop lights at that intersection work well for safety and flow of traffic. The roundabout will certainly cause confusion and acci ...

Response 9-A: This comment is acknowledged. Refer to Response 1-A.

Comment # 10: Open House Comment Cards, September 17, 2025 Comment 10-A: Aerial view needs more labels. I had a hard time understanding how the 5-way was oriented.

Response 10-A: The comment refers to a visual aid provided at the Open House for the Project. This EIR/EA provides the conceptual plan and right-of-way impacts from the Project in Figure 1.4-1 and 1.4-7. These figures provide additional context and visual references for the Project.

Comment 10-B: I’m all for it!
Response 10-B: This comment in support for the Project is acknowledged.

Comment 10-C: Please use California native or low water use plants. The other roundabouts use ugly mortared cobble, pink concrete and non-native plants. We can do better.

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Response 10-C: As described in AMM VIS-1.2 (see Section 2.8 Visual/Aesthetics), the roundabouts, medians, and parkway strips shall be landscaped where feasible.

Decorative paving shall be used for areas too narrow to plant or where planting is not easily maintained. Caltrans requires that native plantings be used in roadway landscaping, whenever feasible. The landscape plans for the Project will incorporate native wildflowers and grasses to support native species and wildlife, including butterflies. The species of plants to be used and the paving materials will be determined during the Project plans, specifications, and estimates (PS&E) phase.

Comment 10-D: I’ve lived here for 62 years and I’ve never really had a problem with the intersection. You learn to deal with it. Waste of money. 2 years of noise and mayhem, no thank you!
Response 10-D: This comment is acknowledged. As described in Section 1.2.2 Need, the Project intersection has been documented via traffic studies to operate at an unacceptable Level of Service (LOS D) and operations are anticipated to continue to deteriorate due to the continued growth of the area and increase in vehicular demand on this intersection. Additionally, the intersection experiences a higher than statewide average collision rate for similar facilities.

Comment 10-E: This meeting was informative. Thank you for having all the city, Caltrans, and design folks here. I’m pro roundabout!
Response 10-E: This comment in support for the Project is acknowledged.

Comment 10-F: It would be helpful to have more than a poster session presentation where residents can ask questions and a panel could answer. Others may have questions that I haven’t thought about but I would be interested in learning the response.

Response 10-F: The comment regarding the format of the Open House is acknowledged. Other written public comments and the City’s responses can be reviewed within this section of the FEIR/EA.

Comment 10-G: It is terrible Mr. Rossi’s house will be demolished. As an Alta Heights native I hate to see that! When this project is done there should be some sort of X-mas tree statue in honor of him. That house was decorated at X-mas for years.

Response 10-G: The demolition of the residence at 801 Silverado Trail has been identified as an adverse effect under NEPA and a significant unavoidable impact under CEQA in this EIR/EA, as described in Section 2.9 Cultural Resources and Section 3.2.5 Cultural Resources. As described in MM CULT-1.1, specific mitigation measures will be carried out in accordance with the Memorandum of Agreement (MOA) developed between Caltrans and the State Historic Preservation Officer (see Appendix I).

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Comment 10-H: My concern is getting out of Alta Heights during high traffic times. I don’t see how we will be able to enter the roundabout with traffic on Silverado trail, heading north, and filling the lanes. This problem would be especially acute during evacuations. We have had 2 in the last few years, keep it the way it is.

Response 10-H: Due to variations in individual driver behaviors including the speed when entering the roundabout, gaps will be available allowing side street traffic to enter the roundabout. Also, presence or crossing of pedestrians in the intersection create additional gaps in the flow of northbound and southbound Silverado Trail vehicular traffic for side streets vehicles to enter the roundabout. During any traffic jams, caused by an emergency, vehicles will be traveling more slowly, allowing opportunities for side street vehicles to merge onto Silverado Trail.

Comment 10-I: Concerned about crossing areas on map. Safety!! School children and myself crossing this area. Bottle neck at Lincoln/Silverado trail and Soscol/Silverado trail.

Response 10-I: The pedestrian crossings have been designed consistent with the National Cooperative Highway Research Program Report 672 entitled “Roundabouts:
an Information Guide, 2nd Edition”. Marked pedestrian crossings would be set back a minimum of one car length from the circulatory roadway and pedestrian refuges at least six feet wide would be provided. These two-stage crossings reduce the amount of sustained time a pedestrian is in potential conflict with motorized vehicles by limiting the length of each crossing and limiting each crossing to one direction of vehicle travel at a time.

Comment 10-J: I would like for it to remain as is.

Response 10-J: This comment is acknowledged. As detailed in Section 1.2 Purpose and Need, the Project is intended to address a variety of community needs and provide access at the intersection for all users.

Comment 10-K: I’m happy to hear about plans to integrate Class I bike lanes on Coombsville Rd in the project, and the signalized crossing in between the round-abouts.

I hope the slopes, in particular on East Ave, don’t become issues. I’m looking forward to the improved traffic flow and reduced tailbacks that I hope will result from this project.

Response 10-K: The Project will provide bicycle and pedestrian facilities through the intersection. The proposed roundabouts will include pedestrian activated Rectangular Rapid Flashing Beacons (RRFB) push buttons to alert vehicular traffic of pedestrian crossings. Due to the slopes on East Avenue, the proposed roundabouts will largely be constructed on fill in order to flatten the roadway grade on the entry and exit points. This design will ensure adequate access for all users.

Comment 10-L: I don’t want this. I don’t know anyone that wants this.

Response 10-L: This comment is acknowledged. As detailed in Section 1.2 Purpose and Need, the Project is intended to address a variety of community needs and provide access at the intersection for all users.

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Comment # 11: Stromberger, Karla, September 18, 2025
Comment 11-A: I attended the meeting last night. Thank you for hosting it. I started a blog on NextDoor two days ago and I am going to copy and paste the most salient comments for you. I know that this is a done deal, but I think you need to take into consideration what the locals are saying. There are SERIOUS concerns! Integrate those concerns into your long term planning!!
I doubt I will still be alive to see this project finished. I do think it is a terrible idea. And I realize it is a done deal! The roundabouts that have been built in Napa are way too small to be safe. I know roundabouts well. I lived in England for 1.5 years and drove all over Europe on many trips in a right hand drive car. We did well with the roundabouts there - they are much larger. The only good roundabout I have seen in Northern California is the one on Corona and South Mountain parkway in Petaluma. It is big enough to handle Semi trucks, firetrucks, and cars at the same time. The space at the five-way intersection is way too small, has too great of a rise (which is poorly reflected on the drawings), and will be unable to accommodate drunk drivers leaving town on weekends, and pedestrians at all times - especially at the beginning and end of the school day. It seems to be a great place for accidents, and major injuries for pedestrians or bicyclists.

Response 11-A: The roundabouts design will be balanced based on the traffic volume, available space and the latest standards for safe and efficient operation. Modern roundabouts are designed to reduce vehicular speed for greater safety of motorized vehicles as well as other users (pedestrians and bicyclists). Larger roundabouts may be used for locations with greater speed limits. The design will reduce both the possibility and severity of accidents. The proposed roundabouts are designed to handle standard trucks and large vehicles. The Project would reduce grades through the roundabouts to improve access for all users and comply with ADA requirements. Overall, statistical data indicate that roundabouts improve both safety and operations for all users.

Comment 11-B: Not every thing from the Blog was posted here because the old lady (ME) didn’t quite know how to do all of this - as I read through it there were several comments that didn’t make it into this. I have removed most last names of those who wrote. At the bottom, all of the posts came up of to the right of the page for some reason. I was again unable to change all of that. some of the comments are missing because they got deleted by accident by me - I don’t know why! This is why you don’t give an elder the job of writing and copying emails. I did leave in about 3-5 positive comments about roundabouts. It would be interesting if someone of you dared to respond to so many issues that people have with roundabouts, and the desire to not make a change.

This is the Start of the NextDoor feed:

Karla Stromberger: This meeting is about the City/county and State wanting to make the 5 way/lights intersection into roundabouts. Apparently this construction cannot happen immediately. But there are several concerns in doing this: during construction will there be exit and entrance possibilities onto East Ave from the present 5 way.? If not, how will the day care on East, the condos on East, and other homes on East South of Montecito

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access their properties? The new LPE at the Church will add a lot to congestion to turn North on East Ave by AH School and residents leaving on Montecito while the project is being constructed. And how will emergency evacuations manage this exiting? And access to the area by first responders. Yes, I know that is a concern of MINE! If you have never been evacuated from this area you could consider refraining from commenting. Show up for this meeting if you have thoughts about the impact of such a change, are curious, or think that waiting a few minutes at the 5 way intersection with present signals is not a big deal! There were 18 positive responses to date to just my comment above!
Response 11-B: Preparation and approval of a Traffic Management Plan (TMP) will be required prior to project construction. As discussed in the EIR/EA, the TMP will identify detour routes as needed and will address all aspects of construction including, but not limited to, traffic handling in each stage of construction, pedestrian safety/access, and bicycle safety/ access. The TMP will consider the access and traffic handling requirements for school schedules and emergency access (refer to Section 2.7.3 of this EIR/EA). Additional responses to a summary of the Nextdoor comments received is provided below.

Comment 11-C: In summary, several of the Nextdoor comments were focused on roundabout operations during events at the Napa Valley Expo and during school drop off and pick up periods of the day.

Response 11-C: This comment is acknowledged. Please refer to Response 6-A.

Comment 11-D: Several of the additional Nextdoor comments expressed concerns related to the City and County approval process and the responsiveness of elected leaders to the community’s concerns.

Response 11-D: This comment is acknowledged. As detailed in Section 1.2 Purpose and Need, the Project is intended to address a variety of community needs and provide access at the intersection for all users. All comments provided by the community on the Project and Draft EIR/EA will be considered as part of the project approval and final design process.

Comment 11-E: Commenters on Nextdoor also raised concerns related to the design of the Project accounting for slopes and pedestrians crossing through the roundabout intersections.

Response 11-E: This comment is acknowledged. Please refer to Responses 10-K and 12-B.

Comment 11-F: Additional commenters on Nextdoor expressed concerns related to accommodating semi-trucks, vehicles hauling boats, and a preference for the existing traffic signal to remain (i.e. the No Build Alternative).

Response 11-F: This comment is acknowledged. Please refer to Responses 6-A and 11-A regarding improved delay at the intersection and the Project design.

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Comment # 12: Wyman, Lynn, October 4, 2025
Comment 12-A: Thank you for reviewing my comments. Whereas single lane roundabouts reduce accidents, the Arizona State University study found that multiple lane roundabouts cause a 60% increase in accidents.

Response 12-A: The Arizona State University study conducted by professor Michael Mamlouk did indicate the reason for increases in accident rates at multiple lane roundabouts is due to the lack of familiarity and training with roundabouts leading to confusion in the usage of multiple lanes in a roundabout. This same article, however, concluded that there were fewer injuries at multi-lane roundabouts. Professor Mamlouk also mentioned that while a traditional intersection has 32 vehicle-to-vehicle contact (conflict) points, a roundabout has eight, and that in the right circumstance, they can be extremely effective.

Comment 12-B: Pedestrian safety at roundabouts needs more study per The Journal of Safety Research. With Silverado Middle School, Napa County Fairgrounds and the residential areas in the proximity of the proposed roundabouts, there are significant amounts of pedestrian traffic through the intersection involved. With the current signals the vehicular traffic is stopped for the pedestrians to cross. With roundabouts, the pedestrian traffic would depend on drivers yielding to them in order to cross. This is a less safe scenario for the pedestrians. Disabled pedestrians prefer intersections without roundabouts. There is a large volume of truck, pickup and suv traffic through this intersection and the drivers of these high profile vehicles do not have good visibility of pedestrians. This creates an unsafe crossing scenario for the pedestrians.

Response 12-B: The proposed roundabouts will include pedestrian activated Rectangular Rapid Flashing Beacons (RRFB) push buttons to alert vehicular traffic of pedestrian crossings. During major events with large number of pedestrians present, event permit requirements will dictate use of traffic controls to assist with allowing pedestrian crossing of the intersection. The use of RRFBs will aid drivers in recognizing the presence of pedestrians intending to cross the street. Limiting the crosswalks to one single lane at a time with breaks in the crossings through construction of islands in between each lane, will allow users to cross shorter distances at one time, as necessary.

Comment 12-C: With an increase in vehicular accidents and unsafe crossings for pedestrians, do not build the roundabouts.

Supporting Evidence A:
https://link.edgepilot.com/s/932b288f/R_ULxnmue0SIcl_5PeVUPw?u=https://urldefense .com/v3/__https://www.wrtv.com/traffic/study-2-lane-roundabouts-cause-increase-in- crashes__%3B!!LWi6xHDyrA!5V-
yGj9TmSFbCDscAe9AgriFvM0gJs1l9thqCuBfTIkiMIuNxOA5_9A7UQKOv8qxNMzcjI6J9 Oic27j7ZHtLx4t3PR5LRw%24
Supporting Evidence B:
https://link.edgepilot.com/s/b9f08613/USG9GPkUlUWkYbB3QXspUQ?u=https://urldefe nse.com/v3/__https://www.sciencedirect.com/science/article/abs/pii/S00224375250007

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75__%3B!!LWi6xHDyrA!6eLdmJMe17KyEwOgWF1UXWP0BuKql651uhALHuxggvVKzb nYg3dDBvk8WM7yGmGPly8M8Tb89FVEgtL5qtPnXoL6nCyIfQ%24
Supporting Evidence C:
https://link.edgepilot.com/s/9962aae0/P-MoO7un7EWm2HLbLNvS3Q?u= https://www.wrtv.com/traffic/study-2-lane-roundabouts-cause-increase-in-crashes Response 12-C: This comment is acknowledged. The Project will be designed to current roundabout design standards and safety provisions for pedestrians and bicyclists, including ADA compliant facilities, will be provided. The use of roundabouts has been shown to reduce the severity of vehicular crashes. The Project would reduce congestion and vehicle delay while improving safety for all users.

Comment # 13: Zeichner, Daniel, and Lockman, Elizabeth, September 15, 2025 Comment 13-A: My wife and I are the owners of a historical 1895 farmhouse which is located at 36 coombsville Road in Napa. We have owned the property since 2019 and have substantially invested in modernizing and updating the property within the survey lines. We have converted a garage to a modern ADU (pool house), added an in ground pool and spa, added extensive outdoor landscaping and bordered the property with a 6- 8 foot privacy fence. In February 2024 a large tree on our property was knocked over into and onto our house requiring 1 1/2 years of renovation which is currently being completed. As we relocated out of town (to Florida) during this time, we have returned to find out that the proposed roundabout project might swallow up our entire property which we were planning to use as a retirement home. We have looked over the Environmental Impact Statement and would appreciate your comments. Thank you for your consideration.

Response 13-A: The Project right-of-way acquisition at 36 Coombsville Road is shown in Figure 1.4-7. The Project would avoid developed areas of the property as much as possible. Access to the property would be maintained with construction of the Project and, therefore, full acquisition of the parcel is not proposed. The City and Caltrans will work with the property owner to acquire portions of the parcel for the Project during the final design phase consistent with Caltrans processes for right-of-way acquisition.

Comment 13-B: 36 Coombsville Rd: Impacts our property much more than we understood. 4 million dollar & renovation
Response 13-B: This comment is acknowledged. Please refer to Response 13-A.

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Chapter 5 List of Preparers
The following individuals were principally responsible for preparing this Final EIR/EA and/or the technical studies upon which the Final EIR/EA is based:

California Department of Transportation, District 4 [Oversight] Maxwell Lammert, Office of Environmental Analysis
Nathan Roberts, Office of Environmental Analysis
Shawn Hallum, Office of Environmental Analysis
Nancy Frost, Office of Biological Sciences and Permit
Sarah Daniel, Office of Biological Sciences and Permits Kristina Montgomery, Office of Cultural Resource Studies Cesar Villanueva, Office of Cultural Resource Studies
Michael Meloy, Office of Cultural Resource Studies
Shilpa Mareddy, Office of Environmental Engineering
Preeti Purandar, Office of Environmental Engineering
Alex McDonald, Office of Landscape Architecture
Teresa Kennedy, Office of Landscape Architecture
Mojgan Osooli, Office of Water Quality
Demeke Tsige, Office of Water Quality
City of Napa [Oversight]
Julie Lucido, Public Works Director
Farid Javandel, Senior Traffic Engineer
Napa Valley Transportation Authority [Oversight]
Danielle Schmitz, Director, Capital Development and Planning Grant Bailey, Program Manager, Engineering

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David J. Powers & Associates, Inc. [EIR/EA Preparation, Community Impacts Memorandum, Hydrology and Water Quality Memorandum]
Will Burns, Vice President and Principal Project Manager Connor Tutino, Project Manager
Ryan Osako, Graphic Artist
GHD [Project Design, Traffic Operations Analysis Report, Noise Abatement Decision Report, Stormwater Data Report, Visual Impact Assessment Memorandum]
Kamesh Vedula, Principal
Ahmad Rahimi, Senior Transportation Engineer
Matt Wargula, Project Manager
Emily Shandy, Project Manager
Michael Pitcock, Senior Transportation Engineer
Mike Masschaele, Air & Noise Service Line Leader
Sam East, Vibrations and Acoustics Professional
Tyler Burkart, Project Landscape Architect
Illingworth & Rodkin, Inc. [Air Quality Report, Energy Analysis, Noise Study Report, Construction Vibration Report]
Jay Witt, Senior Consultant
Heather Bruce, Senior Consultant
Sequoia Ecological Consulting, Inc. [Natural Environment Study (Minimal Impacts)]
Kimberly Oldehoeft, Biologist/Project Manager
Archaeological/Historical Consultants [Archaeological Survey Report, Historical Resources Evaluation Report, Historic Property Survey Report] Daniel Shoup, Principal and Owner
Jennifer Ho, Owner and Senior Historian
Molly Fierer-Donaldson, Senior Archaeologist
Ward Hill, Architectural Historian

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Napa, California July 2026
Parikh Consultants, Inc. [Preliminary Geotechnical Design Report] Frank Wang, Senior Project Engineer
Craig Langbein, Project Geologist
Watearth [Initial Site Assessment, Location Hydraulic Study, Drainage Technical Memorandum]
Jennifer Walker, CEO
Jabob Guise, Water Resources Engineer
Carlos Quispe, Water Resources Engineer

EXHIBIT A

Five-Way Intersection Improvements 208 Final EIR/EA
Napa, California July 2026
Chapter 6 Distribution List
This Final EIR/EA was distributed to the following legislators, public officials, agencies, and organizations:

Legislators and Public Officials
• U.S. Senator Alex Padilla
• U.S. Senator Adam Schiff
• U.S. Representative Mike Thompson
• California Senator Christopher Cabaldon
• California Assemblymember Cecilia Aguiar-Curry
• Napa County Supervisor Joelle Gallagher
• Napa County Supervisor Amber Manfree
• City of Napa Councilmember Mary Luros
State Agencies (via State Clearinghouse)
• California Highway Patrol
• California Department of Fish and Wildlife (Region 3) • California Department of Toxic Substances Control
• Regional Water Quality Control Board (San Francisco Bay Region) • State Historic Preservation Office
• California Transportation Commission
• Air Resources Board
• Native American Heritage Commission
• State Water Resources Control Board
Regional Agencies
• Metropolitan Transportation Commission
• Association of Bay Area Governments

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Five-Way Intersection Improvements 209 Final EIR/EA
Napa, California July 2026
• Bay Area Air District
• Napa Valley Transportation Authority
Local Agencies
• City of Napa
• Napa County Public Works Department
• Napa Valley Unified School District
Native American Tribes
• Mishewal-Wappo Tribe of Alexander Valley
• Yocha Dehe Wintun Nation
Organizations
• Napa County Bicycle Coalition
• Napa County Historical Society
• Napa County Landmarks
• Napa Chamber of Commerce

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Five-Way Intersection Improvements 210 Final EIR/EA
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Chapter 7 References
Archaeological/Historical Consultants. Archaeological Survey Report. Silverado Trail/Coombsville Road 5-Way Intersection. September 2024.

Archaeological/Historical Consultants. Historical Resources Evaluation Report:

Silverado Trail/Coombsville Road 5-Way Intersection. September 2024.

Association of Bay Area Governments and Metropolitan Transportation Commission.

Plan Bay Area 2050. October 21, 2021.

Bay Area Air Quality Management District. “Air Quality Standards and Attainment Status.” Last Updated January 5, 2017. Accessed August 27, 2024.

Bay Area Air Quality Management District. Final 2017 Clean Air Plan. April 19, 2017.

CAL FIRE. Napa County State Responsibility Area Fire Hazard Severity Zones.

Adopted June 15, 2023. https://34c031f8-c9fd-4018-8c5a-4159cdff6b0d-cdn- endpoint.azureedge.net/-/media/osfm-website/what-we-do/community-wildfire- preparedness-and-mitigation/fire-hazard-severity-zones/fire-hazard-severity- zones-map-2022/fire-hazard-severity-zones-maps-2022-
files/fhsz_county_sra_11x17_2022_napa_2.pdf
California Air Resources Board (ARB). 2008. Climate Change Scoping Plan Appendices. Volume II: Analysis and Documentation. Appendix I, p. I-19.

December.
https://ww3.arb.ca.gov/cc/scopingplan/document/scopingplandocument.htm.

Accessed: June 14, 2024.

California Air Resources Board (ARB). 2021. SB 375 Regional Plan Climate Targets. https://ww2.arb.ca.gov/our-work/programs/sustainable-communities- program/regional-plan-targets. Accessed: June 14, 2024.

California Air Resources Board (ARB). 2022a. 2022 Scoping Plan for Achieving Carbon Neutrality. Executive Summary. https://ww2.arb.ca.gov/our-work/programs/ab- 32-climate-change-scoping-plan/2022-scoping-plan-documents. Accessed: June 14, 2024.

California Air Resources Board (ARB). 2022b. Climate Change. https://ww2.arb.ca.gov/our-work/topics/climate-change. Accessed: June 14, 2024.

California Air Resources Board (ARB). 2023. California Greenhouse Gas Emissions Inventory Data–2023 Edition, 2000-2021. https://ww2.arb.ca.gov/ghg-inventory- data. Accessed: June 14, 2024.

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Five-Way Intersection Improvements 211 Final EIR/EA
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California Air Resources Board. “Advanced Clean Cars II.” Accessed August 29, 2024. https://ww2.arb.ca.gov/our-work/programs/advanced-clean-cars- program/advanced-clean-cars-ii
California Air Resources Board. “Overview: Diesel Exhaust and Health.” Accessed August 27, 2024. https://ww2.arb.ca.gov/resources/overview-diesel-exhaust-and- health.

California Department of Conservation. “California Important Farmland Finder.” Accessed April 26, 2024. https://maps.conservation.ca.gov/DLRP/CIFF/ California Department of Conservation. “California Williamson Act Enrollment Finder”.

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California Department of Conservation. “Williamson Act.” http://www.conservation.ca.gov/dlrp/lca.

California Department of Conservation. California Tsunami Maps. Accessed October 1, 2024. https://www.conservation.ca.gov/cgs/tsunami/maps
California Department of Finance. “E-5 Population and Housing Estimates for Cities, Counties, and the State, January 2021-2024, with 2020 Benchmark.” Accessed:

June 4, 2024. Available at:
https://dof.ca.gov/forecasting/demographics/estimates/e-5-population-and- housing-estimates-for-cities-counties-and-the-state-2020-2024/ California Department of Forestry and Fire Protection. “Fire and Resource Assessment Program.” Accessed April 26, 2024. http://frap.fire.ca.gov/.

California Department of Housing and Community Development. “Regional Housing Needs Allocation and Housing Elements” Accessed June 4, 2024. http://hcd.ca.gov/community-development/housing-element/index.shtml.

California Department of Tax and Fee Administration. “Net Taxable Gasoline Gallons.” Accessed August 29, 2024.
https://www.cdtfa.ca.gov/dataportal/dataset.htm?url=VehicleTaxableFuelDist.

California Department of Transportation (Caltrans). 2018. Caltrans Climate Change Vulnerability Assessments. District 4 Technical Report. January. Prepared by WSP. https://dot.ca.gov/programs/transportation-planning/2019-climate-change- vulnerability-assessments.

California Department of Transportation (Caltrans). 2020. Caltrans Greenhouse Gas Emissions and Mitigation Report. Final. August. Prepared by ICF, Sacramento,

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CA. https://dot.ca.gov/programs/public-affairs/mile-marker/summer-2021/ghg.

Accessed: June 14, 2024.

California Department of Transportation (Caltrans). 2021a. California Transportation Plan 2050. February. https://dot.ca.gov/programs/transportation- planning/division-of-transportation-planning/state-planning-equity-and- engagement/california-transportation-plan. Accessed: June 14, 2024.

California Department of Transportation (Caltrans). 2021b. Caltrans 2020-2024 Strategic Plan.
https://storymaps.arcgis.com/stories/f190b9755a184b268719dac9a11153f7.

Accessed: June 14, 2024.

California Department of Transportation. “Scenic Highways.” Accessed September 20, 2024. https://dot.ca.gov/programs/design/lap-landscape-architecture-and- community-livability/lap-liv-i-scenic-highways.

California Department of Transportation. 2023. Sustainable Operations at Caltrans. https://dot.ca.gov/programs/esta/sustainable-caltrans. Accessed: June 14, 2024.

California Department of Transportation. District 4 Regional Board 2 Trash Generation Map. Accessed January 14, 2026.
https://giswest.mbakerintl.com/bakerportal/apps/webappviewer/index.html?id=72 277c8d263749e9b52c8849a6fe8730
California Energy Commission. Energy Consumption Data Management System. “Electricity Consumption by County.” Accessed August 29, 2024. http://ecdms.energy.ca.gov/elecbycounty.aspx.

California Environmental Protection Agency. “Cortese List Data Resources.” Accessed June 5, 2024. https://calepa.ca.gov/sitecleanup/corteselist/.

California Governor’s Office of Planning and Research (OPR). 2015. A Strategy for California @ 50 Million. November. https://opr.ca.gov/planning/environmental- goals/. Accessed: June 14, 2024.

California Natural Resources Agency. 2022. Nature-Based Climate Solutions: Natural and Working Lands Climate Smart Strategy.
https://resources.ca.gov/Initiatives/Expanding-Nature-Based-Solutions.

Accessed: June 14, 2024.

California Natural Resources Agency. 2023. California Climate Adaptation Strategy. https://climateresilience.ca.gov/overview/index.html. Accessed: June 14, 2024.

California Ocean Protection Council. 2022. State Agency Sea-Level Rise Action Plan for California. February. https://www.opc.ca.gov/climate-change/sea-level-rise-2/.

Accessed: June 14, 2024.

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Five-Way Intersection Improvements 213 Final EIR/EA
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California Regional Water Quality Control Board San Francisco Region. Municipal Regional Stormwater NPDES Permit, Order No. R2-2022-0018, NPDES Permit No. CAS612008. May 11, 2022.

California State Transportation Agency. 2021. Climate Action Plan for Transportation Infrastructure (CAPTI). https://calsta.ca.gov/subject-areas/climate-action-plan.

Accessed: June 14, 2024.

California State Water Resources Control Board. “2020-2022 California Integrated Report (Clean Water Act Section 303(d) List and 305(b) Report).” May 11, 2022.

Accessed October 1, 2024.
https://www.waterboards.ca.gov/water_issues/programs/water_quality_assessm ent/2020_2022_integrated_report.html.

CARB. 2022 Scoping Plan for Achieving Carbon Neutrality. December 2022.

City of Napa. “Parks Locations & Amenities”. Accessed August 9, 2024. https://www.cityofnapa.org/356/Parks-Locations-Amenities City of Napa. General Plan Update Partial Recirculated Draft Environmental Impact Report (SCH# 2021010255) . June 2022.

Climate-Safe Infrastructure Working Group. 2018. Paying it Forward: The Path Toward Climate-Safe Infrastructure in California. September.
https://resources.ca.gov/CNRALegacyFiles/docs/climate/ab2800/AB2800_Climat e-SafeInfrastructure_FinalNoAppendices.pdf. Accessed: June 14, 2024.

Federal Highway Administration (FHWA). 2022. Sustainability. https://www.fhwa.dot.gov/environment/sustainability/resilience/. Last updated July 29, 2022. Accessed: June 14, 2024.

Federal Highway Administration (FHWA). No date. Sustainable Highways Initiative. https://www.fhwa.dot.gov/environment/sustainability/initiative/. Accessed: June 14, 2024.

FEMA. Flood Insurance Rate Map No. 06055C0517F. Effective September 29, 2010.

GHD. Traffic Operations Analysis Report: Napa “Five-Way Intersection” Improvements.

July 2024.

GHD. Visual Impact Assessment Memorandum: Intersection Improvements at Silverado Trail (SR 121)/Third Street/Coombsville Road/East Avenue (“Five-Way Intersection”). September 2024.

GreatSchools.org. “Find Your School District and Nearby Schools”. Accessed August 9, 2024. https://www.greatschools.org/school-district-boundaries-map/

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Five-Way Intersection Improvements 214 Final EIR/EA
Napa, California July 2026
Illingworth & Rodkin, Inc. Air Quality Report: Intersection Improvements at Silverado Trail (SR 121)/Third Street/Coombsville Road/East Avenue (“Five-Way Intersection”). May 2025.

Illingworth & Rodkin, Inc. Construction Vibration Report: Intersection Improvements at Five-Way Intersection Project. April 2025.

Illingworth & Rodkin, Inc. Energy Analysis for the Intersection Improvements at Silverado Trai (SR 121)/Third Street/Coombsville Road/East Avenue. September 2024.

Illingworth & Rodkin, Inc. Noise Study Report: Intersection Improvements at Five-Way Intersection Project. September 2024.

Napa County Airport Land Use Commission. Airport Land Use Compatibility Plan.

Revised December 1999. Figure 5C Airport Impact Areas.

National Oceanic and Atmospheric Administration (NOAA). 2022. 2022 Sea Level Rise Technical Report.
https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelrise-tech-report.html.

Accessed: November 13, 2023.

North Pacific Anadromous Fish Commission. “Species: What is an Anadromous Fish?”.

Accessed September 3, 2024. https://www.npafc.org/species/ Page & Turnbull, Inc. Historic Context Statement & Survey Report – Soscol Gateway/East Napa. January 11, 2012.

Parikh Consultants, Inc. Preliminary Geotechnical Design Report: Intersection Improvements at Silverado Trail (SR 121)/Third Street/Coombsville Road/East Avenue (“Five-Way Intersection”). August 2024.

Sequoia Ecological Consulting, Inc. Natural Environment Study (Minimal Impacts):

Intersection Improvements at Silverado Trail (SR 121)/Third Street/Coombsville Road/East Avenue (“Five-Way Intersection”). August 2024.

State of California. 2018. California’s Fourth Climate Change Assessment. http://www.climateassessment.ca.gov/. Accessed: June 14, 2024.

U.S. Department of Transportation (U.S. DOT). 2014. Corporate Average Fuel Economy (CAFE) Standards.
https://www.transportation.gov/mission/sustainability/corporate-average-fuel- economy-cafe-standards. Accessed: June 14, 2024.

U.S. Department of Transportation. 2023. Climate Action. January. https://www.transportation.gov/priorities/climate-and-sustainability/climate-action.

Accessed: June 14, 2024.

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U.S. Energy Information Administration. “Petroleum & Other Liquids, California Field Production of Crude Oil.” Accessed August 29, 2024.
https://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=pet&s=mcrfpca1&f=a U.S. Environmental Protection Agency (U.S. EPA). 2021. Final Rule to Revise Existing National GHG Emissions Standards for Passenger Cars and Light Trucks Through Model Year 2026. December. https://www.epa.gov/regulations- emissions-vehicles-and-engines/final-rule-revise-existing-national-ghg-emissions.

Accessed: June 14, 2024.

U.S. Environmental Protection Agency. 2024a. Data Highlights. Inventory of U.S.

Greenhouse Gas Emissions and Sinks: 1990-2022.
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and- sinks. Accessed: June 14, 2024.

U.S. Environmental Protection Agency. 2024b. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2022. https://www.epa.gov/ghgemissions/inventory- us-greenhouse-gas-emissions-and-sinks. Accessed: June 14, 2024.

U.S. Global Change Research Program. 2023. Fifth National Climate Assessment. https://nca2023.globalchange.gov/chapter/front-matter/. Accessed: June 14, 2024.

United State Department of Agriculture, Natural Resources Conservation Service. “Soil Survey Geographic (SSURGO) Database for Napa County, California, Western Part, ca055”. 2019.

United States Department of Energy. Energy Independence & Security Act of 2007.

Accessed August 29, 2024. http://www.afdc.energy.gov/laws/eisa.

United States Department of Transportation. USDOT Announces New Vehicle Fuel Economy Standards for Model Year 2024-2026.” Accessed August 29, 2024. https://www.nhtsa.gov/press-releases/usdot-announces-new-vehicle-fuel- economy-standards-model-year-2024-2026
United States Energy Information Administration. “California State Energy Profile.” Accessed August 29, 2024. https://www.eia.gov/state/print.php?sid=CA.

United States Environmental Protection Agency. “EPA Actions to Protect the Public from Exposure to Asbestos.” Accessed June 5, 2024.
https://www.epa.gov/asbestos/epa-actions-protect-public-exposure-asbestos United States Environmental Protection Agency. “Summary of the Resource Conservation and Recovery Act.” Accessed June 5, 2024.
https://www.epa.gov/laws-regulations/summary-resource-conservation-and- recovery-act.

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United States Environmental Protection Agency. “Superfund: CERCLA Overview.” Accessed May 11, 2020. https://www.epa.gov/superfund/superfund-cercla- overview.

United States Environmental Protection Agency. “The 2023 EPA Automotive Trends Report: Greenhouse Gas Emissions, Fuel Economy, and Technology since 1975.” December 2023. https://www.epa.gov/system/files/documents/2023- 12/420r23033.pdf
United States Geological Survey. U.S. Landslide Inventory and Susceptibility Map.

Accessed September 10, 2024.
https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=ae120962f4594 34b8c904b456c82669d
Watearth. Drainage Technical Memorandum: City of Napa Five-Way Intersection Project. August 2024.

Watearth. Initial Site Assessment: City of Napa Five-Way Intersection Project. May 2024.

Watershed Information & Conservation Council. WICC Interactive Map. Accessed October 1, 2024. https://www.napawatersheds.org/maps

EXHIBIT A
Appendix A Final Individual Section 4(f)
Evaluation
Five-Way Intersection Improvements
Project

NAPA, CALIFORNIA
DISTRICT 4 –NAP–121 (PM 7.2/7.5)
0J890/0414000097
Final Individual Section 4(f) Evaluation

Prepared by the
State of California, Department of Transportation
and the City of Napa
The environmental review, consultation, and any other actions required by applicable Federal environmental laws for this project are being, or have been, carried out by Caltrans pursuant to 23 USC 327 and the Memorandum of Understanding dated May 27, 2022, and executed by FHWA and Caltrans.

July 2026

EXHIBIT A
Five-Way Intersection Improvements A-i Final Individual Section 4(f) Evaluation Napa, California July 2026
Table of Contents
Appendix A Final Individual Section 4(f) Evaluation ................................................... i Chapter 1 Introduction............................................................................................... 1 Chapter 2 Description of the Proposed Project ......................................................... 2

2.1 PURPOSE AND NEED ...................................................................................... 2

2.1.1 Purpose ....................................................................................................... 2

2.1.2 Need ............................................................................................................ 2

2.2 PROJECT DESCRIPTION ................................................................................. 3

2.3 PROJECT ALTERNATIVES ............................................................................... 7

2.3.1 Build Alternative ........................................................................................... 7

2.3.2 No Build Alternative ................................................................................... 18 Chapter 3 Section 4(f) Properties ............................................................................ 19

3.1 801 Silverado Trail and East Napa Historic District .......................................... 19 Chapter 4 Use of the Section 4(f) Property ............................................................. 21 Chapter 5 Avoidance Alternatives ........................................................................... 23

5.1 No-Build Alternative ......................................................................................... 24

5.2 Alternative 1: Four-Legged Roundabout .......................................................... 25

5.3 Alternative 2: Five-Legged Roundabout ........................................................... 28

5.4 Alternative 3: Two Roundabouts ...................................................................... 31

5.5 Alternative 4: Two Signalized Intersections ...................................................... 34 Chapter 6 Measures to Minimize Harm to the Section 4(f) Property ................... .... 39 Chapter 7 Least Harm Analysis and Concluding Statement ............................... ....41 Chapter 8 Coordination ....................................................................................... ....43

8.1 Native American Consultation ...................................................................... ....43

8.2 Section 106 Consultation ............................................................................. ....45 Chapter 9 Resources Evaluated Relative to the Requirements of the Section 4(f):

No-Use Determination(s) ........................................................................................... ....47

9.1 Napa Valley Expo .............................................................................................47

9.2 Residential and Commercial Properties ....................................................... ....47

9.3 Tulocay Cemetery ........................................................................................ ....48

EXHIBIT A
Five-Way Intersection Improvements A-ii Final Individual Section 4(f) Evaluation Napa, California July 2026
List of Tables
Table 2.3-1: Project Right-of-Way Impacts .................................................................... 15 Table 5.5-1: Section 4(f) Alternatives Summary ............................................................ 37 List of Figures
Figure 2.2-1: Regional Map ............................................................................................. 4 Figure 2.2-2: Vicinity Map ................................................................................................ 5 Figure 2.2-3: Aerial Photograph with Surrounding Land Uses ........................................ 6 Figure 2.3-1: Conceptual Roundabout Plan .................................................................... 8 Figure 2.3-2: Roundabout Cross-Sections ...................................................................... 9 Figure 2.3-3: SR 121 Cross-Sections ............................................................................ 10 Figure 2.3-4: Roadway Cross Sections ......................................................................... 11 Figure 2.3-5: 3D Perspective Overviews ....................................................................... 12 Figure 2.3-6: Representative Street Approaches .......................................................... 13 Figure 2.3-7: Right-of-Way Impacts............................................................................... 16 Figure 3.1-1: Section 4(f) Resources Location Map ...................................................... 20 Figure 5.2-1: Alternative 1 ............................................................................................. 26 Figure 5.3-1: Alternative 2 ............................................................................................. 29 Figure 5.4-1: Alternative 3 ............................................................................................. 33 Figure 5.5-1: Alternative 4 ............................................................................................. 36

EXHIBIT A

Five-Way Intersection Improvements A-1 Final Individual Section 4(f) Evaluation Napa, California July 2026

Chapter 1 Introduction
Section 4(f) of the Department of Transportation Act of 1966, codified in federal law at 49 United States Code (USC) 303, declares that “it is the policy of the United States Government that special effort should be made to preserve the natural beauty of the countryside and public park and recreation lands, wildlife and waterfowl refuges, and historic sites.”
Section 4(f) specifies that the Secretary of Transportation may approve a transportation program or project . . . “requiring the use of publicly owned land of a public park, recreation area, or wildlife and waterfowl refuge of national, state, or local significance, or land of an historic site of national, state, or local significance (as determined by the federal, state, or local officials having jurisdiction over the park, area, refuge, or site) only if:
• There is no prudent and feasible alternative to using that land; and • The program or project includes all possible planning to minimize harm to the park, recreation area, wildlife and waterfowl refuge, or historic site resulting from the use.”
Section 4(f) further requires coordination with the Department of the Interior and, as appropriate, the involved offices of the Department of Agriculture and the Department of Housing and Urban Development in developing transportation projects and programs that use lands protected by Section 4(f). If historic sites are involved, then coordination with the State Historic Preservation Officer is also needed.

Responsibility for compliance with Section 4(f) has been assigned to Caltrans pursuant to 23 USC 326 and 327, including determinations and approval of Section 4(f) evaluations, as well as coordination with those agencies that have jurisdiction over a Section 4(f) resource that may be affected by a project action.

EXHIBIT A

Five-Way Intersection Improvements A-2 Final Individual Section 4(f) Evaluation Napa, California July 2026

Chapter 2 Description of the Proposed
Project

2.1 PURPOSE AND NEED

2.1.1 Purpose
The purpose of the Five-Way Intersection Improvements Project (Project) is to improve the operations of the intersection that will result in reduced driver delay, reduced congestion, and, therefore, an overall improvement to intersection operations.

Additionally, the purpose of the Project is to improve the safety and accessibility for all users of the intersection. The secondary objectives of this Project are to improve bicycle and pedestrian facilities at the intersection as well as meet Americans with Disabilities (ADA) requirements.

2.1.2 Need
The Project intersection needs geometric improvements to improve the operations, efficiency, and capacity of the intersection. In addition, safety improvements are needed to reduce collisions through the SR 121 (Silverado Trail) corridor, which is ranked among the highest injury corridors within the City of Napa per the City’s Local Roadway Safety Plan (adopted September 6, 2022). Data was obtained and analyzed from both the Caltrans Traffic Accident Surveillance and Analysis System (TASAS) and the City of Napa Police Department for the latest 5-year period in the Project area along SR 121.

There were ten reported collisions within the Project area, which resulted in a higher than statewide average rate for similar facilities.

Traffic studies conducted by the City of Napa have shown that the intersection has operated at a Level of Service (LOS) D since at least the year 2000. Although the intersection is already operating at an unacceptable LOS,44 operations will continue to deteriorate due to the continued growth of the area and continued increase in vehicular demand on this intersection, as documented in the Napa-Solano Travel Demand Model.

The existing intersection has limited and substandard pedestrian facilities,45 including long, skewed crosswalks and narrow sidewalks, that increase pedestrian exposure to vehicle conflicts throughout the five-legged intersection. Existing pedestrian facilities do not meet current Americans with Disabilities Act (ADA) standards. There are discontinuous sidewalks on the northwest and southwest sides of SR 121 that extend for approximately 50 feet and 200 feet, but no other sidewalks exist at the intersection.

The existing intersection also does not provide bicycle facilities, resulting in a disconnect in the existing bicycle facilities along Third Street, Coombsville Road, and East Avenue.

44 The City’s LOS standard for the intersection is mid-LOS E which is exceeded under existing conditions. 45 Substandard pedestrian facilities include discontinuous sidewalks and lack of ADA compliance.

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Five-Way Intersection Improvements A-3 Final Individual Section 4(f) Evaluation Napa, California July 2026

2.2 PROJECT DESCRIPTION
This section describes the proposed action and the Project alternatives developed to meet the purpose and need of the Project, while avoiding or minimizing environmental impacts. The alternatives are the “Build Alternative” and the “No-Build Alternative.” The Project is located in Napa County on State Route 121 at its intersection with Third Street, Coombsville Road, and East Avenue. Regional and vicinity maps are shown in Figure 2.2-1 and Figure 2.2-2, respectively. An aerial photograph of the Project site and the surrounding land use is shown in Figure 2.2-3. The Project proposes to improve the intersection by constructing two, modern, single-lane roundabouts with curb, gutter, ramps, sidewalk, streetlights, and storm drain improvements. The proposed Project would ease traffic congestion by introducing a traffic-calming circulation pattern, improving community connectivity in the Project area, and improving pedestrian and bicycle safety within and adjacent to the intersection. Local circulation and access would largely remain unchanged. The Project intersection geometrics and pedestrian crossings are consistent with the National Cooperative Highway Research Program (NCHRP) Report 672 entitled “Roundabouts: An Information Guide, 2nd Edition” (Guide).

EXHIBIT A

Five-Way Intersection Improvements A-7 Final Individual Section 4(f) Evaluation Napa, California July 2026

2.3 PROJECT ALTERNATIVES

2.3.1 Build Alternative

2.3.1.1 SR 121/Third Street/Coombsville Road/East Avenue Intersection A double roundabout with four legs on the northerly roundabout and three legs on the southerly roundabout would accommodate the Design Year traffic volumes. Retaining walls will be required to minimize adjacent property impacts along Coombsville Road and East Avenue. Along Coombsville Road, a retaining wall minimizes grading impacts that would otherwise require removal of multiple mature trees. Along East Avenue, the retaining wall minimizes encroachment onto the parcel at the northeast corner of the intersection with SR 121 to maintain economic viability of the commercial parcel. Due to the steep entry grades coming into/out of East Avenue and Coombsville Road, the new roundabout intersections will largely be in fill in order to flatten the roadway grade on the entry/exits. Minor regrading on approaches where the Project conforms to existing roadways will be required, but would be a maximum excavation of three to five feet. A conceptual plan is shown in Figure 2.3-1, cross-sections are shown in Figure 2.3-2 through Figure 2.3-4, and 3D renderings are shown in Figure 2.3-5 and Figure 2.3-6.

2.3.1.2 Pedestrian and Bicycle Safety
A 10-foot wide shared-use path will be provided throughout the new roundabout(s) buffered by at least 2 feet of landscaping from the roadway. The shared-use path conveys both pedestrian and bicycle traffic through the intersection. Ramps will provide access to and from the shared-use path for bicyclists. Each leg of the two roundabouts will conform to existing bikeways as appropriate. In the existing condition, there are no dedicated bicycle facilities on SR 121 north of the Project (though bicyclists are permitted on the roadway). There are Class II Bicycle Lanes46 on SR 121 south of the Project. Northbound bicyclists on SR 121 approaching the Project will have an option to either merge from the bicycle lane into the travel lane and navigate the intersection using the circulating lanes or use the provided bike ramp to access the shared-use path and navigate using marked crossings; southbound bicyclists leaving the Project will re- enter the bicycle lane using either the provided bike ramp, if they are on the shared-use path, or by merging from the travel lane, if they are in the roadway.

46 Class II Bike Lanes provide an exclusive space for bicyclists in the roadway and are established by painting lines and symbols on the roadway surface.

EXHIBIT A
0 25 50 100 200 Feet
CONCEPTUAL ROUNDABOUT PLAN FIGURE 2.3-1

EXHIBIT A

SOUTH ROUNDABOUT

NORTH ROUNDABOUT
ROUNDABOUT CROSS-SECTIONS FIGURE 2.3-2

EXHIBIT A
ROUTE 121 BETWEEN ROUNDABOUTS
ROUTE 121 NORTH OF ROUNDABOUT ROUTE 121 SOUTH OF ROUNDABOUT SR 121 CROSS-SECTIONS FIGURE 2.3-3

EXHIBIT A
3RD STREET

COOMBSVILLE ROAD EAST AVENUE
ROADWAY CROSS-SECTIONS FIGURE 2.3-4

EXHIBIT A
Source: GHD, Inc.

NORTH ROUNDABOUT SOUTH ROUNDABOUT
3D PERSPECTIVE OVERVIEWS FIGURE 2.3-5

EXHIBIT A

THIRD STREET APPROACH
Source: GHD Inc. SOUTHBOUND SR 121 APPROACH AT THIRD STREET REPRESENTATIVE STREET APPROACHES FIGURE 2.3-6

EXHIBIT A

Five-Way Intersection Improvements A-14 Final Individual Section 4(f) Evaluation Napa, California July 2026

oncoming drivers in the circulating lane, and exiting drivers to clear the circulating lane before yielding to a pedestrian or bicyclist. Pedestrian refuges at the splitter islands are at least 6 feet wide (consistent with the NCHRP Guide). These two-stage crossings reduce the amount of sustained time a pedestrian is in potential conflict with motorized vehicles by limiting the length of each crossing and limiting each crossing to one direction of vehicle travel at a time.

2.3.1.3 Reduced Speed and Collision Potential
The geometric design of roundabouts typically requires drivers to reduce speed in the intersection to 15-25 mph. At signalized intersections, drivers are typically able to travel through the intersection at speeds higher than posted limits due to the lack of geometric constraints. Because of these reduced travel speeds through the intersection and expected reduction in crashes, the Project is likely to eliminate the most severe crash types.

2.3.1.4 Structures
Retaining walls will be required to minimize adjacent property impacts along Coombsville Road and East Avenue, type selection will be completed later this phase to finalize type and size of wall, however every effort will be made to minimize footings (currently anticipated to be approximately three to five feet deep) to reduce potential environmental and right of way impacts.

2.3.1.5 Right of Way
Four commercial properties have driveway access points within the Project area that will be replaced/adjusted as needed. Business access will be provided throughout the construction process in coordination with business property owners.

One vacant parcel and one residential property will require full/major acquisition in order to construct the new roundabout(s) and minimize the overall impacts within the Project vicinity.

EXHIBIT A

Five-Way Intersection Improvements A-15 Final Individual Section 4(f) Evaluation Napa, California July 2026

In addition, minor frontage impacts to adjacent parcels may be required in order to conform the roundabout(s) and/or shared use path to existing facilities. These minor frontage impacts include driveway conforms or realignments. Work would primarily occur through a Temporary Construction Easement (TCE) but may require some minor right-of-way acquisition so that the City will own the sidewalks to facilitate maintenance while Caltrans will own the highway up to the back edge of the curb on both sides of SR 121. TCEs from 802 and 820 Juarez Street, as well as permanent acquisitions from 801 Silverado Trail and 820 Juarez Street, would occur within the East Napa Historic District. The Project’s potential right-of-way impacts are summarized in Table 2.3-1 and shown in Figure 2.3-7 on the following page. For private residences, the addresses are included and for commercial properties, the business names are identified.

Table 2.3-1: Project Right-of-Way Impacts
Impact Type Full Property
(Assessor’s Parcel Number)
Partial Property
(Assessor’s Parcel Number)
Temporary
Easement
006-147-003 (820 Juarez Street)
006-147-005 (802 Juarez Street)
006-147-008 (El Rancho Grande)
006-148-010 (Napa Tire & Wheels)
006-148-012 (commercial center)
006-151-010 (Posh Motors)
006-152-001 (Napa Marble & Granite Works)
006-152-002 (1010 East Avenue)
006-211-010 (36 Coombsville Road)
Permanent
Acquisition
006-147-004 (801 Silverado Trail) 006-147-003 (820 Juarez Street) 006-147-008 (El Rancho Grande)
006-148-010 (Napa Tire & Wheels)
006-148-012 (commercial center)
006-151-010 (Posh Motors)
006-152-001 (Napa Marble & Granite Works)
006-152-002 (1010 East Avenue)
006-211-010 (36 Coombsville Road)

EXHIBIT A
Source: GHD, December 17, 2024.

LEGEND:

ACQUISITION

TEMPORARY CONSTRUCTION EASEMENT

PROPOSED RIGHT OF WAY LINE

PARCEL LINE
EAST Ave
COOMBSVILLE Rd
THIRD St
ROUTE 121
ROUTE 121

STATE R/W

STATE R/W
JUAREZ St
TAYLOR St1
2 3
4 5
7 8
9 10
6 CITY R/W

CITY R/W

CITY R/W
PARCEL

NUMBER APN ADDRESS GRANTOR OWNER

OCCUPIED

ROW ACQUISTION TYPE

PERMANENT
(SF)

TEMPORARY

CONSTRUCTION

EASEMENT (SF)
1 006-147-005 802 JUAREZ ST ROSSI, CHARLES P TRUST NO 540 2 006-147-004 801 SILVERADO TR ROSSI, CHARLES P TRUST YES 8240 3 006-147-003 820 JUAREZ ST RICE, MARGARET YES 2140 900 4 006-147-008 891 SILVERADO TR

GARCIA, JOSE & SONIA
TRUST NO 120 440
5 006-151-010 800 SILVERADO TR KISER, LANCE C NO 1020 1370 6 006-148-012
325, 333, 341, 343
3RD ST
BROWN, RAY D JR. & E LYNN
TRUST NO 220 1240
7 006-148-010 713 SILVERADO TR AOK LLC NO 2630 2150
8 006-211-010 36 COOMBSVILLE RD

ZEICHNER, DANEIL MATHEW
LOCKMAN, ELIZABETH NO 12160 2370
9 006-152-001 9 COOMBSVILLE RD

MCNERNE Y-SIMICH, SUE W
TRUST
C/0 NAPA MARBLE &
GRANITE WORKS NO 140 295
10 006-152-002 1010 EAST AVE

MCNERNE Y-SIMICH, SUE W
TRUST
C/0 NAPA MARBLE &
GRANITE WORKS NO 30 1710
Total 26700 11015
0 25 50 100 200 Feet
RIGHT-OF-WAY IMPACTS FIGURE 2.3-7

EXHIBIT A

Five-Way Intersection Improvements A-17 Final Individual Section 4(f) Evaluation Napa, California July 2026

2.3.1.6 Utilities
Due to the grading that will be required to construct the new roundabout(s), relocation of the City water transmission line that runs from 3rd Street as well as up to six joint utility poles will need to be relocated or undergrounded. All are anticipated to occur within existing or proposed right of way. In addition, adjustment of utility vaults to match the final pavement surface elevation would be required along SR 121 and some fill materials may be required depending on cover and new conform grading requirements.

All other existing utilities would be protected in place.

2.3.1.7 Construction
Construction is anticipated to begin in 2027 and to last approximately 18 months.

2.3.1.8 Depth of Disturbance
Excavation would be required throughout the Project in order to construct utility relocations (approximately three to six feet deep depending on utility), lighting, landscaping and drainage facilities, which require trenching, placement of pipe, drainage structures, landscaping, irrigation, and backfill to a depth of six feet. A

EXHIBIT A

Five-Way Intersection Improvements A-18 Final Individual Section 4(f) Evaluation Napa, California July 2026

maximum excavation depth of 10 feet may be required to install foundations for retaining walls along the Coombsville Road and East Avenue legs.

2.3.2 No Build Alternative
The No Build Alternative leaves the existing lane geometrics and intersection controls in place, without a roundabout. Under existing conditions, the intersection of SR 121/Third Street/Coombsville Road/East Avenue remains signalized. This alternative does not meet the purpose and need for the Project to improve intersection operations.

EXHIBIT A

Five-Way Intersection Improvements A-19 Final Individual Section 4(f) Evaluation Napa, California July 2026

Chapter 3 Section 4(f) Properties

3.1 801 Silverado Trail and East Napa Historic District The Build Alternative would impact one protected Section 4(f) historic property, the East Napa Historic District. For the purposes of this Project only, the district is considered eligible under NRHP Criteria A, for its association with the City of Napa’s Italian American community settlement and working-class residential development, and under Criteria C, as a surviving example of a working-class neighborhood with high level of architectural integrity. Caltrans CSO approved the consideration of eligibility on August 27, 2024. The 70 properties within the district are considered contributors to the district’s historical integrity. One of them, 801 Silverado Trail, was determined not individually eligible for the NRHP and SHPO concurred with that finding on April 7, 2025. Nevertheless, the construction of one of the two roundabouts requires the demolition of the building at 801 Silverado Trail, resulting in an adverse effect to the East Napa Historic District per the 106 PA, Stipulation X.C. Figure 3.1-1 shows the location of the East Napa Historic District, of the building at 801 Silverado Trail, and of the Project site.

EXHIBIT A

Five-Way Intersection Improvements A-21 Final Individual Section 4(f) Evaluation Napa, California July 2026

Chapter 4 Use of the Section 4(f) Property
This chapter discusses the Section 4(f) use of the Build Alternative and the historic residential property at 801 Silverado Trail, as a contributing property to the East Napa Historic District, as described in Chapter 3 of this document. As defined in 23 CFR 774.17, “use” of Section 4(f) property occurs:

1. When land is permanently incorporated into a transportation facility.

2. When there is a temporary occupancy of land that is adverse in terms of the statute’s preservation purpose as determined by the criteria in 23 CFR 774.13(d).

CFR 774.13(d) indicates that temporary occupancies of land that are so minimal as to not constitute a use within the meaning of Section 4(f) are exceptions to the requirement for Section 4(f) approval. Specifically, for the purposes of Section 4(f), such temporary occupancy of a Section 4(f) resource does not normally constitute “use” if each of the following five conditions is met 23 CFR 774.13(d):
a. Duration must be temporary (i.e., less than the time needed for construction of the project), and there should be no change in ownership of the land;
b. Scope of work must be minor (i.e., both the nature and the magnitude of the changes to the Section 4(f) property are minimal);
c. There are no anticipated permanent adverse physical impacts, nor would there be interference with the protected activities, features, or attributes of the property, on either a temporary or permanent basis; d. The land being used must be fully restored (i.e., the property must be returned to a condition that is at least as good as that which existed prior to the project); and
e. There must be documented agreement of the official(s) with jurisdiction over the Section 4(f) resource regarding the above conditions.

3. When there is a constructive use of a Section 4(f) property as determined by the criteria in 23 CFR 774.15. 23 CFR 774.15(a) indicates a constructive use occurs when the transportation project does not incorporate land from a Section 4(f) property, but the project’s proximity impacts are so severe that the protected activities, features, or attributes that qualify the property for protection under Section 4(f) are substantially impaired. Substantial impairment occurs only when the protected activities, features, or attributes of the property are substantially diminished.

A historic district is considered a Section 4(f) resource if the historic district is listed or determined eligible for listing in the NRHP. An individual property within a historic district is subject to consideration under Section 4(f) if it is on or eligible for the NRHP

EXHIBIT A

Five-Way Intersection Improvements A-22 Final Individual Section 4(f) Evaluation Napa, California July 2026

individually or if it is an element that is considered "contributing" to the characteristics that qualify the historic district as an eligible property. Impacts to non-contributing elements of a historic district would not constitute a Section 4(f) use.

Definition of Effect and Criteria of Adverse Effect
The definition of effect is contained within 36 CFR 800.16(i), “Effect means alteration to the characteristics of a historic property qualifying it for inclusion in or eligibility for the National Register.” An adverse effect, as contained in 36 CFR Part 800.5(a)(1) occurs “when an undertaking may alter, directly or indirectly, any of the characteristics of a historic property that qualify the property for inclusion in the National Register in a manner that would diminish the integrity of the property’s location, design, setting, materials, workmanship, feeling, or association per.” Adverse effects may include reasonably foreseeable effects caused by the undertaking that may occur later in time, be farther removed in distance, or be cumulative.

Use of the Section 4(f) Property Under the No-Build Alternative The No-Build Alternative would not include any of the elements of the Build Alternative; therefore, it would not result in the use of any land from a Section 4(f) property and there would be no impacts to the residence at 801 Silverado Trail or any other properties listed in Table 2.3-1. The No Build Alternative is an avoidance alternative assessed in Chapter 5.

Use of the Section 4(f) Property Under the Build Alternative The Build Alternative would result in the full right-of-way purchase of the property at 801 Silverado Trail for permanent incorporation into the proposed roundabout transportation facility. The existing residence would be demolished. This would constitute an adverse effect under Section 106 as the residence is a contributing resource to the East Napa Historic District, which is considered an eligible resource for the purposes of this analysis; therefore, there is a Section 4(f) use to the historic district because there is an anticipated Section 106 adverse effect due to the removal of a contributing property from the historic district.

EXHIBIT A

Five-Way Intersection Improvements A-23 Final Individual Section 4(f) Evaluation Napa, California July 2026

Chapter 5 Avoidance Alternatives
Section 4(f) specifies that Caltrans may approve a project requiring the use of Section 4(f) property only if there are no prudent and feasible avoidance alternatives to the use of Section 4(f) resources and that the proposed action includes all possible planning to minimize harm to the affected resources. 23 CFR 774.17 defines a feasible and prudent avoidance alternative as follows:

1. A feasible and prudent avoidance alternative avoids using Section 4(f) property and does not cause other severe problems of a magnitude that substantially outweighs the importance of protecting the Section 4(f) property. It is appropriate to consider the relative value of the resource to the preservation purpose of the statute.

2. An avoidance alternative is not feasible if it cannot be built as a matter of sound engineering judgment.

3. An avoidance alternative is not prudent if it:
i. Compromises the project so that it is unreasonable given the Purpose and Need;
ii. Results in unacceptable safety or operational problems; iii. After reasonable mitigation, still causes:
a) Severe social, economic, or environmental impacts;
b) Severe disruption to established communities;
c) Severe environmental justice impacts; or
d) Severe impacts to other federally protected resources. iv. Results in additional construction, maintenance, or operational costs of an extraordinary magnitude;
v. Causes other unique problems or unusual factors; or
vi. Involves multiple factors listed above that, while individually minor, cumulatively cause unique problems or impacts of extraordinary magnitude.

Alternatives Considered
Thirteen conceptual build alternatives were originally designed for the Project, which were narrowed into three build alternatives during the Project Initiation Document (PID) phase, and one build alternative during the Project Approval & Environmental Document

EXHIBIT A

Five-Way Intersection Improvements A-24 Final Individual Section 4(f) Evaluation Napa, California July 2026

(PA&ED) phase. Alternatives were eliminated prior to and during the PID phase primarily based on their ability to meet the Project’s Purpose and Need, excessive costs, unacceptable traffic operations, and imposed access restrictions.

All previously developed concepts were considered for their ability to avoid Section 4(f) protected properties. Six alternatives were moved forward within the Section 4(f) analysis to determine if these alternatives were feasible and prudent avoidance alternatives to avoid the use of the historic district. The potential alternatives were further reviewed to determine if they were feasible as a matter of sound engineering judgment and prudent as described for each alternative below. Out of the six alternatives, two alternatives were determined to be redundant as they had similar designs to two of the other alternatives. Therefore, the six alternatives were narrowed down to four alternatives by combining the alternatives that otherwise would have been considered redundant. Additionally, the No-Build Alternative would avoid the Section 4(f) protected property (i.e., the historic district).

5.1 No-Build Alternative
Under the No-Build Alternative, there would be no action and the improvements associated with the Build Alternative would not be constructed. The feasibility factor, therefore, is not relevant to the No Build Alternative. The following addresses components that inform the prudency factors, as listed above. i. The No Build Alternative would compromise the Project to a degree that it is unreasonable to proceed in light of the purpose and need because it would not address the existing operational deficiencies that result in vehicle delay and congestion and would not address the existing bicycle and pedestrian safety concerns at the Project intersection.
ii. As discussed above, the No Build Alternative would result in operational problems because it would not address the existing unacceptable level of service (LOS) conditions at the Project intersection that will worsen over time as vehicle traffic increases. The No Build Alternative would also not address the existing bicycle and pedestrian safety problems or make any improvements to address the high collision rates at the Project intersection.
iii. The No Build Alternative would not cause severe social, economic, or environmental impacts, severe disruptions to established communities, or severe impacts to federally protected resources.
iv. The No Build Alternative would not result in additional construction, maintenance, or operational costs of an extraordinary magnitude.
v. The No Build Alternative would not cause other unique problems or unusual factors.
vi. The No Build Alternative would not cumulatively result in impacts of extraordinary magnitude.

EXHIBIT A

Five-Way Intersection Improvements A-25 Final Individual Section 4(f) Evaluation Napa, California July 2026

Weighing all of the circumstances, it appears the No Build Alternative would not be considered feasible and prudent in light of the factors set forth in 23 CFR 774.17 (i) and (ii), as initially analyzed above.

The following alternatives were considered for their ability to avoid Section 4(f) protected properties. Although a considerable amount of time, design effort, resources, and early public outreach were done for this analysis during the Project delivery phases for PID/planning and PA&ED, not all alternatives completely avoid the contributing property to the East Napa Historic District. As can be seen in the figures where the conceptual design alternatives reflect a very small area of design that overlaps the historic residential property at 801 Silverado Trail, which is a contributing property to the East Napa Historic District. The following paragraphs demonstrate the due diligence conducted by the Project delivery team in an attempt to avoid the Section 4(f) property.

5.2 Alternative 1: Four-Legged Roundabout
Alternative 1 would construct a four-legged roundabout that would connect directly to SR 121 and Third Street and would connect to East Avenue and Coombsville Road via a T-intersection, as shown in Figure 5.2-1.

The paragraphs below discuss the six factors that inform feasibility and prudency. i. Alternative 1 would compromise the Project to a degree that it is unreasonable to proceed with in light of the purpose and need because it would not improve operations of the Project intersection. The T-intersection of East Avenue and Coombsville Road would likely operate poorly as there would be a high volume of vehicles traveling northwest on Coombsville Road and making a left turn toward the roundabout. These conditions of high volume of vehicles and left turn movements would fail to meet the Project’s purpose of improving intersection operations to reduce driver delay and congestion. Therefore, according to this factor, Alternative 1 has been determined not to be feasible and prudent. ii. As discussed above, Alternative 1 would result in operational problems due to an anticipated high volume of vehicles that would travel northwest on Coombsville Road making a left turn toward the roundabout, resulting in vehicle queuing at the T-intersection of Coombsville Road and East Avenue and unacceptable LOS conditions. Therefore, according to this factor, Alternative 1 has been determined not to be feasible and prudent.

EXHIBIT A
ROUTE 121
ROUTE 121
EAST Ave
3RD St
COOMBSVILLE Rd
y r e t e m e C y a c o l u T
East Napa
Historic District
0 20 40 80 Feet
ALTERNATIVE 1 FIGURE 5.2-1

EXHIBIT A

Five-Way Intersection Improvements A-27 Final Individual Section 4(f) Evaluation Napa, California July 2026

iii. Alternative 1 would not cause severe environmental impacts or impacts to federally protected environmental resources. However, Alternative 1 would result in a full acquisition of one commercial property and a major impact to at least one additional commercial property, potentially resulting in social and economic impacts to the local community. The potential right-of-way impacts are summarized below:
a) Napa Marble & Granite Works (9 Coombsville Road) is a monument and grave marker business. The existing commercial structure falls within the footprint of the proposed connection between East Avenue/Coombsville Road and the four-legged roundabout, requiring full acquisition of the property and demolition of the structure.
b) Napa Tire & Wheels (713 Silverado Trail) is an automobile service business. The southbound SR 121 exit from the four-legged roundabout would impact the existing overhang/carport structure on the property. Both existing driveways would be closed off because of the design footprint for the roundabout, and there may not be a suitable location to provide a new driveway that gives sufficient distance from the roundabout. This would lead to a high probability for full acquisition of the parcel for the impacted property and business. Additionally, due to the nature of the business, contaminated soils are likely present in the area.
c) 1010 East Avenue is a multi-family residential property with two residences that would be directly impacted by the connection of Coombsville Road to East Avenue. Full acquisition of the property and demolition of the residences would be required.
iv. Alternative 1 would result in additional costs associated with an increased number of property acquisitions, including two businesses (Napa Marble & Granite Works and Napa Tires & Wheels). Additionally, there is likely contaminated soil on the Napa Tire & Wheels property due to the nature of the existing business that would require remediation and monitoring, which would also add costs to the Project. These costs, while an increase compared to the proposed Build Alternative, are not anticipated to be of an extraordinary magnitude.
v. While the Napa Marble & Granite Works property is not a listed historic resource, the family-owned business has been in operation for nearly 80 years and there is a strong relationship between the business and the nearby Tulocay Cemetery, which introduces a unique problem because this business makes grave markers and headstones for Tulocay Cemetery.
vi. Alternative 1 would result in an increased number of property acquisitions, including up to two businesses. This alternative would acquire the Napa Marble & Granite Works property and result in a major impact on or full acquisition of the Napa Tires & Wheels property. This alternative would also acquire two residences at 1010 East Avenue. These factors would cumulatively result in

EXHIBIT A

Five-Way Intersection Improvements A-28 Final Individual Section 4(f) Evaluation Napa, California July 2026

impacts to the existing community character and local economy by demolishing several existing buildings surrounding the Project intersection and displacing up to two residences and two businesses. In particular, displacement of the Napa Marble & Granite Works business would cause a unique problem for the Tulocay Cemetery, an assumed Section 4(f) property, due to its existing business relationship of purchasing grave markers and headstones from Napa Marble & Granite Works. Therefore, according to this factor, Alternative 1 has been determined not to be feasible and prudent.

Weighing all of the circumstances, Alternative 1 is not considered as feasible and prudent in light of the factors in 23 CFR 774.17 (i), (ii), and (vi), as analyzed above.

5.3 Alternative 2: Five-Legged Roundabout
Alternative 2 would construct a single, five-legged roundabout, as shown in Figure

5.3-1.

The paragraphs below discuss the six factors that inform feasibility and prudency. i. Alternative 2 would not compromise the Project so that it is unreasonable given the purpose and need. Alternative 2 would address the purpose and need of the Project because it would reduce conflict points at the Project intersection; however, it may compromise the operation and safety element of the purpose and need as compared to the Project.
ii. Alternative 2 would not result in unacceptable safety or operational problems because it would improve existing conditions; however, the five-legged roundabout would increase traffic delays, pedestrian crossing distances, and vehicular speeds as compared to the Project.
iii. Alternative 2 would not cause severe environmental impacts or impacts to federally protected environmental resources. However, Alternative 2 could result in a full acquisition of three commercial properties and full acquisition of a residential property, potentially resulting in social and economic impacts to the local community. The potential right-of-way impacts are summarized below:
a) Napa Marble & Granite Works (9 Coombsville Road) is a monument and grave marker business. The property would be completely within the footprint of the roundabout and would require full acquisition. b) Posh Motors is a used car dealership which uses the parking lot on their property to store and display inventory. Alternative 2 may eliminate both existing driveways for the Posh Motors (800 Silverado Trail) property. If both driveways are eliminated, full acquisition of the property would be required.

EXHIBIT A
ROUTE 121
ROUTE 121
EAST Ave
3RD St
COOMBSVILLE Rd
y r e t e m e C y a c o l u T
East Napa
Historic District
0 20 40 80 Feet
ALTERNATIVE 2 FIGURE 5.3-1

EXHIBIT A

Five-Way Intersection Improvements A-30 Final Individual Section 4(f) Evaluation Napa, California July 2026

c) Napa Tire & Wheels (713 Silverado Trail) is an automobile service business. The southbound SR 121 exit from the five-legged roundabout would impact the existing overhang/carport structure on the property. Both existing driveways would be impacted, and there may not be a suitable location to provide a new driveway that gives sufficient distance from the roundabout. Discussion with the business owners will determine if full acquisition is required. Additionally, due to the nature of the business, contaminated soils are likely present in the area.
d) 1010 East Avenue is a multi-family residential property with two residences that would be directly impacted by Alternative 2. The main residence is within the alignment for East Avenue and would require demolition. An additional residence is directly adjacent to the improvements and a new driveway access to the property may be infeasible, requiring full acquisition of the property. iv. Alternative 2 would result in additional costs associated with an increased number of property acquisitions, including up to three businesses (Napa Marble & Granite Works, Posh Motors, and Napa Tire & Wheels) and one multi-family residential property. Additionally, there is likely contaminated soil on the Napa Tire & Wheels property due to the nature of the existing business that would require remediation and monitoring, which would also add costs to the Project.

These costs, while an increase compared to the proposed Build Alternative, are not anticipated to be of an extraordinary magnitude, however, these cost increases could bring into question the reasonableness for the expenditure of public funds.
v. While the Napa Marble & Granite Works property is not a listed historic resource, the family-owned business has been in operation for nearly 80 years and there is a strong relationship between the business, which introduces a unique problem because this business makes grave markers and headstones for Tulocay Cemetery.
vi. Alternative 2 would result in an increased number of property acquisitions, including up to three businesses (Napa Marble & Granite Works, Posh Motors, and Napa Tire & Wheels) and residence(s) at 1010 East Avenue. These factors would cumulatively result in impacts to the existing community character and local economy by demolishing several existing buildings surrounding the Project intersection and displacing up to two residences and three businesses. In particular, displacement of the Napa Marble & Granite Works business would cause a unique problem for the Tulocay Cemetery, an assumed Section 4(f) property, due to its existing business relationship of purchasing grave markers and headstones from Napa Marble & Granite Works.

Additionally, cumulative projects in the area are anticipated to result in network changes to SR 121 to address cut through traffic at Hennessey Drive, including left-turn restrictions. The implementation of left-turn restrictions at Hennessey

EXHIBIT A

Five-Way Intersection Improvements A-31 Final Individual Section 4(f) Evaluation Napa, California July 2026

Drive, a likely outcome of the roundabout construction, would result in operational deficiencies on Third Street (LOS E). Unacceptable LOS conditions along Third Street would cause unique problems for the local community because Third Street connects local residential and commercial uses to SR 121 and Napa’s downtown area, west of the Project intersection. These factors would cumulatively result in unique problems for the existing community character and local economy, resulting in severe disruption to an established community.

Therefore, according to this factor, Alternative 2 has been determined not to be feasible and prudent.

Weighing all of the circumstances, Alternative 2 would result in incrementally worse operations, increased property acquisition, increased costs from right-of-way and environmental remediation, cause unique problems for the community due to the removal of several businesses including Napa Marble & Granite Works, and result in unacceptable LOS conditions along Third Street as a result of cumulative projects in the area, as described above. Alternative 2 is not considered feasible and prudent in light of the factors in 23 CFR 774.17 (vi), as analyzed above.

5.4 Alternative 3: Two Roundabouts
Similar to the proposed Build Alternative, Alternative 3 would construct two roundabouts at the Project intersection. However, Alternative 3 would reroute Third Street to the southern roundabout rather than the northern roundabout, as shown in Figure 5.4-1.

The paragraphs below discuss the six factors that inform feasibility and prudency. i. Alternative 3 would compromise the Project to a degree that it is unreasonable to proceed in light of the purpose and need because it would not improve intersection operations. The AM and PM peak hour queues for southbound vehicles on SR 121 entering the southern roundabout would likely extend more than 150 feet, which is the available distance between the two roundabouts. This would result in the queue spilling back into the northern roundabout, creating significant delay. This would not meet the purpose and need to improve intersection operations and reduce vehicle delay and congestion. Therefore, according to this factor, Alternative 3 has been determined not to be feasible and prudent.
ii. As discussed above, Alternative 3 would result in operational problems because the AM and PM peak hour queues for southbound vehicles on SR 121 entering the southern roundabout would likely extend more than 150 feet, which is the available distance between the two roundabouts. This would result in the queue spilling back into the northern roundabout, creating significant delay. Therefore, according to this factor, Alternative 3 has been determined not to be feasible and prudent.
iii. Alternative 3 would not cause severe environmental impacts or impacts to federally protected environmental resources. However, Alternative 3 would result in a full acquisition of three commercial properties and a major or full acquisition

EXHIBIT A

Five-Way Intersection Improvements A-32 Final Individual Section 4(f) Evaluation Napa, California July 2026

of a fourth commercial property, potentially resulting in social and economic impacts to the local community. The potential right-of-way impacts are summarized below:
a) Posh Motors is a used car dealership which uses the parking lot on their property to store and display inventory. Alternative 3 would require acquisition of a significant portion of the parking area, which eliminates the commercial viability of the property as a car dealership. A full acquisition would be anticipated.
b) Third Street would be realigned through the center of the Napa Tire & Wheels property, and a full acquisition would be required. Due to the nature of the business, contaminated soils are likely present in the area. c) Both existing driveways to the Napa Marble & Granite Works property would be eliminated and there are no viable locations to provide a new driveway. A full acquisition would be required.
d) The commercial center on the southeast corner of Third Street and Juarez Street includes multiple businesses, including an appliance store, plumbing showroom, and children’s event venue. Third Street would be realigned through the property, requiring demolition of a portion of the existing building. Some commercial utility of the remaining unused property may be possible, and an existing driveway onto Juarez Street would remain. Major acquisition would be anticipated, though full acquisition may be required depending on discussions with the property owners.
e) The residential property at 1010 East Avenue would require partial acquisition and may require driveway realignment.

EXHIBIT A
YIELD
YIELD
YIELD
YIELD
YIELD
YIELD
YIELD
YIELD
YIELD
ROUTE 121
ROUTE 121
EAST Ave
3RD St
COOMBSVILLE Rd
y r e t e m e C y a c o l u T
East Napa
t c i r t s i D c i r o t s i H
0 20 40 80 Feet
ALTERNATIVE 3 FIGURE 5.4-1

EXHIBIT A

Five-Way Intersection Improvements A-34 Final Individual Section 4(f) Evaluation Napa, California July 2026

iv. Alternative 3 would result in additional costs associated with an increased number of property acquisitions, including up to three businesses (Napa Marble & Granite Works, Napa Tires & Wheels, and Posh Motors), potential full acquisition of the commercial center at Third Street and Juarez Street, and partial acquisition of the residential property at 1010 East Avenue. There would also likely be additional cost associated with soil remediation and monitoring for the Napa Tire & Wheels property. These costs, while an increase compared to the proposed Build Alternative, are not anticipated to be of an extraordinary magnitude, however, these cost increases could bring into question the reasonableness for the expenditure of public funds.
v. While the Napa Marble & Granite Works property is not a listed historic resource, the family-owned business has been in operation for nearly 80 years and there is a strong relationship between the business, which makes grave markers and headstones, and the nearby Tulocay Cemetery.
vi. Alternative 3 would result in an increased number of property acquisitions, including up to three business parcels (Napa Marble & Granite Works, Napa Tires & Wheels, and Posh Motors), a portion of a commercial center including at least one business, and partial acquisition of 1010 East Avenue. These factors would cumulatively result in impacts to the existing community character and local economy by demolishing several existing buildings surrounding the Project intersection and displacing up to three businesses. In particular, displacement of the Napa Marble & Granite Works business would cause a unique problem for the Tulocay Cemetery, an assumed Section 4(f) property, due to its existing business relationship of purchasing grave markers and headstones from Napa Marble & Granite Works. Therefore, according to this factor, Alternative 3 has been determined not to be feasible and prudent.

Weighing all of the circumstances, Alternative 3 is not considered as feasible and prudent in light of the factors in 23 CFR 774.17 (i), (ii), and (vi), as analyzed above.

5.5 Alternative 4: Two Signalized Intersections
Alternative 4 would reroute Coombsville Road to intersect with SR 121 south of Third Street, creating a new intersection. The existing five-way intersection would be reduced to a four-way intersection of SR 121, Third Street, and East Avenue. A conceptual plan of Alternative 4 is shown in Figure 5.5-1.

The paragraphs below discuss the six factors that inform feasibility and prudency. i. Alternative 4 would compromise the Project to a degree that it is unreasonable to proceed in light of the purpose and need because it would not improve operations or bicycle and pedestrian safety. The closely spaced signalized intersections could create queues for SR 121 through traffic that conflict or spill back into the other intersection, causing delay. Long, skewed crossings for bicyclists and pedestrians would remain, which contribute to safety concerns.

EXHIBIT A

Five-Way Intersection Improvements A-35 Final Individual Section 4(f) Evaluation Napa, California July 2026

Therefore, according to this factor, Alternative 4 has been determined not to be feasible and prudent.
ii. As discussed above, Alternative 4 would likely result in poor operating conditions and would not improve existing conditions for bicycle and pedestrian safety. The closely spaced signalized intersections could create queues for SR 121 through traffic that conflict or spill back into the other intersection, causing delay. Long, skewed crossings for bicyclists and pedestrians would remain, which contribute to safety concerns. Therefore, according to this factor, Alternative 4 has been determined not to be feasible and prudent.
iii. Alternative 4 would not cause severe environmental impacts or impacts to federally protected environmental resources. However, Alternative 4 would require major acquisition from at least one residential property (36 Coombsville Road) to reroute Coombsville Road to a new three-legged signalized intersection. If suitable driveway access cannot be maintained for Napa Marble & Granite Works, full acquisition of the property may be required, potentially resulting in social and economic impacts to the local community. iv. Alternative 4 would not result in additional construction, maintenance, or operational costs of an extraordinary magnitude.
v. While the Napa Marble & Granite Works property is not a listed historic resource, the family-owned business has been in operation for nearly 80 years and there is a strong relationship between the business, which makes grave markers and headstones, and the nearby Tulocay Cemetery.
vi. Alternative 4 would not cumulatively result in unique problems or impacts of extraordinary magnitude.

Weighing all of the circumstances, Alternative 4 is not considered as feasible and prudent in light of the factors in 23 CFR 774.17 (i) and (ii), as analyzed above.

Based on the discussions above, it appears that there are no feasible and prudent alternatives that would avoid the Section 4(f) use of the contributing property to the East Napa Historic District.

A summary of Alternatives 1 through 4, and the feasibility and prudence factor evaluations is provided in Table 5.5-1, following Figure 5.5-1.

EXHIBIT A
Tulocay Cemetery
3rd St
ROUTE 121
EAST Ave
COOMBSVILLE Rd
ROUTE 121
East Napa
Historic District
0 20 40 80 Feet
ALTERNATIVE 4 FIGURE 5.5-1

EXHIBIT A

Five-Way Intersection Improvements A-37 Final Individual Section 4(f) Evaluation Napa, California July 2026

Table 5.5-1: Section 4(f) Alternatives Summary
Alt. Description
Avoid Impacts
to other
Section 4(f)
Resources

1. Compromises
the Purpose and
Need (P&N)

2. Safety or
Operational
Problems

3. After mitigation, still causes social, economic, or
environmental impacts; disproportionate impacts to minority or low-income populations; or severe impacts to other Federally- protected environmental resources

4. Additional
construction,
maintenance, or
operational costs of
extraordinary magnitude

5. Other unique
problems or
unusual factors

6. Involves multiple factors that cumulatively cause
unique problems or impacts of extraordinary
magnitude
1 Four-legged
roundabout
for SR 121
and 3rd
Street with
connection
to T-
intersection
for East
Avenue and
Coombsville
Road
Yes
Care would
need to be
taken to ensure
no impacts to
the cemetery.

Yes, compromises
the P&N because
it does not improve
operations
The T-intersection
of East Avenue/
Coombsville Road
likely operates
poorly, with high
volumes of
vehicles traveling
northwest on
Coombsville Road
and making a left
turn toward the
roundabout.

According to this
factor, Alternative
1 has been
determined not to
be feasible and
prudent.

Operational
Problems
The T-intersection
of East Avenue/
Coombsville Road
likely operates
poorly, with high
volumes of vehicles
traveling northwest
on Coombsville
Road and making a
left turn toward the
roundabout
resulting in
unacceptable LOS.

According to this
factor, Alternative 1
has been
determined not to
be feasible and
prudent.

This alternative would result in a full acquisition of one commercial property and a major impact to at least one additional commercial property:
− Napa Marble & Granite Works (9 Coombsville Road) is a monument and grave marker business. The structure falls in the footprint of the proposed connection between East Ave/
Coombsville Road and the new four-legged roundabout,
requiring full acquisition of the property and demolition of the structure.
− Napa Tire & Wheels (713 Silverado Trail) is an automobile service business. The southbound SR 121 exit from the
roundabout would impact the existing overhang/car port
structure on the property. Both existing driveways would be closed off because of the design footprint of the roundabout, and it may be challenging to identify an acceptable location to provide a new driveway that provides sufficient distance from the roundabout. This would lead to a high probability for full acquisition of the parcel. Due to the nature of the business, contaminated soils are likely present in the area.
− This alternative would also acquire two residences on the multi- family residential parcel at 1010 East Avenue.

There would be additional
costs associated with
right-of-way acquisition,
including two businesses.

There would also likely be
additional cost associated
with soil remediation and
monitoring for the Napa
Tire & Wheels property.

These costs would be an
increase but are not
anticipated to be of an
extraordinary magnitude.

While Napa Marble
& Granite Works (9
Coombsville Road)
is not a listed
historic resource,
the family-owned
business has been
in operation for
nearly 80 years
and there is a
strong relationship
between the
business and the
nearby Tulocay
Cemetery, which
introduces a
unique problem
because this
business makes
grave markers and
headstones for
Tulocay Cemetery.

Napa City CouncilSeptember 15, 2026

Napa City Council
September 15, 2026